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L.  B.   Cat.  No.  1137 

Ube  IRural  Science  Series 

Edited  by  L.  H.  BAILEY 


CITRUS   FRUITS 


Eije  Eural  <Srifncc  Series 

Thk  Soil.     King. 

The  Spraying  ok  Plants.     Lodcman. 

Milk  ASD  ITS  Products.    Wing.   Enlarged  and  Revised. 

The  Fertility  of  the  Land.     Roberts. 

The     Principles    of     Fruit-growing.     Bailey.     20th 

Edition,  Revised. 
Bush-fruits.     Card. 
Fertilizers.     Voorhees. 
The  Principles  of  Agriculture.   Bailey.   15th  Edition, 

Revised. 
Irrigation  and  Drainage.     King. 
The  Farmstead.     Roberts. 
Rural  Wealth  and  Welfare.     Fairchild. 
The  Principles  of  Vegetable-gardening.   Bailey. 
Farm  Poultry.     Watson.    Enlarged  and  Revised. 
The  Feeding  of  Animals.     Jordan. 
The  Farmer's  Business  Handbook.     Roberts. 
The  Diseases  of  Animals.     Mayo. 
The  Horse.     Roberts. 
How  TO  Choose  a  Farm.     Hunt. 
Forage  Crops.     Voorhees. 

Bacteria  in  Relation  to  Country  Life.     Lipnian. 
The  Nursery-book.     Bailey. 
Plant-breeding.     Bailey  and  Gilbert.     Revised. 
The  Forcing-book.     Bailey. 
The  Pruning-book.     Bailey. 

Fruit-growing  in  Arid  Regions.   Paddock  and  Whipple. 
Rural  Hygiene.     Ogden. 
Dry-farming.     Widtsoe. 
Law  for  the  American  Farmer.     Green. 
Farm  Boys  and  Girls.     McKeever. 
The  Training  and  Breaking  of  Horses.     Harper. 
Sheep-farming  in  North  America.     Craig. 
Cooperation  in  Agriculture.     Poicell. 
The  Farm  Woodlot.     Cheyney  and  Wentling. 
Household  Insects.     Herrick. 
Citrus  Fruits.     Coit. 


THE   WASHINGTON    NAVEL  ORANGE 


CITKUS  FRUITS 


AN   ACCOUNT   OF   THE    CITRUS    FRUIT    INDUSTRY 

WITH  SPECIAL  REFERENCE  TO  CALIFORNIA 

REQUIREMENTS    AND    PRACTICES 

AND    SIMILAR    CONDITIONS 


BY 


J.   ELIOT  COIT,  M.S.A.,  Ph.D. 

PROFESSOR    OF    CITRICULTURE     IN    THE     UNIVERSITY    OF    CALI- 
FORNIA   AND    CITRICULTURIST    TO    THE     UNIVERSITY    OF 
CALIFORNIA  AGRICULTURAL  EXPERIMENT  STATION 
FORMERLY    SUPERINTENDENT    IN    CHARGE 
CITRUS     EXPERIMENT     STATION 
RIVERSIDE,   CALIFORNIA 


THE   MACMILLAN   COMPANY 
1922 

JU  rights  reserved 


* 


V9 


Copyright,  1915, 
By  the  MACMILLAN  COMPANY. 


Set  up  and  electrotyped.     Published  April,  1915. 


Nortoooti  ^rcBS 

J.  S.  Gushing  Co.  —Berwick  &  Smith  Co. 

Norwood,  Mass.,  U.S.A. 


LIBRARY 

N„  C.  State  College 


PREFACE 

The  citrus  industry  has  now  reached  a  high  state  of 
development  in  both  California  and  Florida.  Further- 
more, it  is  progressing  with  rapid  strides.  Old  World 
practices  and  precedents  have  been  largely  ignored  in 
the  development  of  an  industry  characteristically  Amer- 
ican in  spirit  and  new  in  methods.  The  readiness  with 
which  the  growers  adopt  new  and  better  methods  is  an 
indication  of  the  vij'ility  and  youthful  vigor  of  this  new 
industry. 

The  literature  has  hardly  kept  pace  with  the  industry 
and  is  scattered  through  a  large  number  of  periodicals 
and  reports.  On  this  account,  it  is  largely  unavailable 
to  those  who  need  it  most.  The  last  comprehensive 
work  published  in  California  was  that  of  Lelong  in 
1902.  This  quickly  ran  out  of  print  and  for  the  last 
six  years  has  been  rare. 

The  present  volume  represents  an  attempt  to  discuss 
underlying  principles  in  such  a  way  as  to  emphasize 
the  importance  of  certain  stable  fundamentals  upon 
which  the  rapidly  cJianging  superstructure  is  built. 
It  has  also  been  the  aim  to  describe  the  industry  as 
it  exists  to-day,  and  bring  together  in  orderly  arrange- 
ment all  the  information  available  at  this  time  which 
is  worth  while. 


11947 


vi  Preface 

The  autlior  has  enjoyed  the  co()i)eratioii  ami  assist- 
ance of  many  friends.  The  cliapter  on  History  and 
Development  has  been  read  and  criticised  by  J.  M. 
Guinn  of  Los  Angeles.  Professors  E.  J.  Wickson, 
E.  B.  Babcock,  B.  A.  Etcheverry,  W.  T.  Home, 
and  H.  J.  Quayle,  together  with  Messrs.  W.  S. 
Reed  and  E.  O.  Essig,  have  kindly  read  and  criti- 
cised parts  of  the  manuscript.  E.  G.  Dezell  of  the 
California  Fruit  Growers'  Exchange  read  the  chap- 
ter on  Marketing.  I  am  indebted  to  my  co-worker, 
I.  J.  Condit,  for  contributing  parts  of  the  chapters  on 
insects  and  fumigation.  For  cordial  cooperation  in 
taking  the  atmometer  records  reported  on  in  Chapter 
XII,  I  am  under  obligation  to  W.  M.  Mertz  of  the 
Citrus  Experiment  Station.  Some  historical  and  other 
data  used  in  Chapter  XIV  on  ''  Frosts  and  Orchard 
Heating  "  has  been  taken  from  the  excellent  graduat- 
ing thesis  of  Carl  Nichols. 

For  the  use  of  certain  illustrations  I  am  indebted  as 
follows:  to  Carl  Nichols  for  Nos.  10,  14,  15,  64,  65, 
and  86;  to  W.  I.  Jones  for  Nos.  57  and  58;  to  the 
Roeding  &  Wood  Nursery  Company  for  Nos.  110, 
111,  &  119;  to  L.  H.  Moore  for  Nos.  113  and  120;  to 
Professor  H.  S.  Fawcett  for  No.  128 ;  to  Professor 
H.  J.  Quayle  for  Nos.  139,  141,  142,  143,  144,  145,  and 
147 ;  and  to  Professor  C.  W.  Woodworth  for  No.  151. 


J.   ELIOT   COIT. 


Berkeley,  California, 
February  17,  1915. 


CONTENTS 


CHAPTER   I 

PAOES 
HiSTOKY    AND    DEVELOPMENT 1-24 

First  planting  of  orange  seeds  in  California,  1  —  first 
commercial  orchard,  2  —  other  pioneer  plantings,  S  — 
early  citrus  fairs,  5  —  the  panic  of  1884-1886,  6  —  the 
cottony  cushion  scale,  organization  of  cooperative 
marketing,  8  —  California  citrus  shipments,  9  —  other 
factors  which  have  made  for  progress,  10  —  history 
of  the  Washington  Navel  orange,  13  —  the  citrus  industry 
in  Arizona  and  Sonora,  23 


CHAPTER   II 

Geography  and  Climatology  of  California  .         .         .         25-39 
Classification  of  citrus  areas,  26  —  southern  coast,  28 
—  interior  valley,  30  —  northern  coast,   31  —  the  frost 
hazard,  33  —  atmospheric  humidity,  34  —  winds,  36  — 
sunlight,  38 

CHAPTER   III 

Botany,  Gross  Structure,  and  Habits  of  Growth  .  40-64 
Classification,  42 — conspectus,  43  —  structure  of  the 
citrus  plant,  45  —  roots,  45  —  wood,  46  —  leaves,  49  — 
thorns,  51  —  flowers,  52  —  pollination  and  seed  forma- 
tion, 55  —  polyembryony,  59 — structure  and  composi- 
tion of  the  fruit,  60  —  seasons  of  blossoming  and  harvest, 
63  — longevity,  64 

vii 


ContcnU 


CHAPTER   IV 

I'AGES 

Varieties 65-83 

Seedling  trees  no  longer  planted,  65  —  the  struggle  be- 
tween many  varieties,  60  —  the  survivors  few  in  num- 
ber, 66  —  the  orange,  description  of  varieties,  66  — 
the  lemon,  description  of  varieties,  72  —  the  pomelo, 
description  of  varieties,  75  —  the  mandarin,  descrip- 
tion of  varieties,  78  —  the  Swingle- Webber  hybrids, 
description  of  varieties,  79  —  the  citron,  80  —  the  shad- 
dock, 81  —  the  lime,  81 — the  kumquat,  83  —  the  sweet 
lemon,  83  —  the  trifoliata,  83 

CHAPTER   V 

The  Citrus  Nursery 84-105 

The  seed-bed,  84  —  source  and  cost  of  seed,  86  — 
preparation  and  planting  of  seed-bed,  87  —  eradication 
of  scale  from  nursery  trees,  90  —  planting  seed-bed  stock, 
91 — propagation,  92  —  cutting  bud- wood,  93  —  storing 
bud-wood,  94  —  time  of  budding,  95  —  method  of  bud- 
ding, 95  —  training  the  nursery  tree,  100  —  balling  and 
shipping,  102 

CHAPTER  VI 
Horticultural  Inspection  and  Quarantine  Service  .  106-113 
The  California  State  Commission  of  Horticulture,  106 
—  inspection  of  interstate  shipments,  107 — quarantine 
orders,  109  —  State  Fruit  Growers'  Conventions,  109  — 
the  County  Commissioners  of  Horticulture,  110  —  duties 
of  county  commissioners,  110  —  compulsory  fumigation, 
110  —  the  necessity  for  inspection,  111 

CHAPTER   VII 
Improvement  of  Citrus  Fruits  by  Breeding  .         .         .     114-131 
Hybridization,  115  — structure  of  citrus  flower,  1 15  — 
cross-pollination,  116  —  improvements  most  needed,  118 


Contents 


—  vegetative  mutations  or  bud-sports,  118  —  kinds  of 
variations,  119 — fluctuations,  119  —  mutations,  120  — 
sectorial  chimeras  or  mixed  plants,  121 — performance 
records  needed,  124 — record  of  West  Highland  Grove, 
125  — selection  of  bud-wood,  128  —  pedigreed  stock,  130 

CHAPTER   VIII 

Judging  Citrus  Fruits 132-138 

Orange  score-card,  133  —  orange  standards,  133  — 
lemon  score-card,  134  —  lemon  standards,  135  —  pomelo 
score-card,  136  —  pomelo  standards,  136  —  packed  box 
score-card,  137  —  packed  box  standards,  137  —  exhibit 
scoie-card,  138 

CHAPTER   IX 
Selection  of  Site  and  Preparation  for  Planting         .     139-146 
Selection  of  site,  139  —  score-card  for  citrus  lands,  139 

—  the  frost  question,  140  —  water  supply,  141  —  soil 
adaptations,  142  —  clearing  and  leveling  land,  145  — 
amelioration  of  hardpan  by  the  use  of  dynamite,  146 

CHAPTER   X 

Planting  the  Orchard 147-164 

Orchard  plans,  147  —  number  of  trees  per  acre,  149  — 
distance  of  planting,  149  —  contour  planting,  151  —  time 
of  planting,  151  —  root-stocks,  151  —  digging  the  holes, 
155  —  setting  the  trees,  156  —  intercropping,  159  —  the 
cost  of  planting,  100 

CHAPTER   XI 
Cultivation,  Fertilization,  Cover-crops         .         .         .     165-186 
Plowing,    165  —  cultivating,    168  —  mulching,    173  — 
orchard  tractors,  174  —  fertilizing,  175  —  humus,  178  — 
green  manure   crops,  181  —  summary  of  soil   manage- 
ment, 184 


X  Contents 

CHAPTER   XII 

PAGES 

Ikrigation 187-20.3 

Amount  of  water  needed,  188  —  atmometer  records, 
18!)  — sources  and  cost  of  water,  102  —  methods  of  dis- 
tribution, 193  —  time  of  application,  195  —  methods  of 
application,  198 

CHAPTER   XIII 

Pruning  and  Topworking 204-229 

Pruning  trees  in  the  nursery  row,  205  —  pruning 
oranges,  207  —  suckers  versus  fruit  wood,  209 — prun- 
ing lemons,  213— disposition  of  prunings,  217 — prun- 
ing frosted  trees,  217  —  reheading  young  trees,  218  — 
reheading  mature  trees,  220  —  topworking  old  trees,  223 
—  pruning  tools,  225  —  wounds  and  dressings,  226 

CHAPTER   XIV 

Frost  and  Orchard  Heating 230-276 

Historical  cold  periods,  230  —  season  of  frost  in  Cali- 
fornia, 231 —  forecasting  frosts,  233  —  factors  influenc- 
ing the  occurrence  of  frost,  2.34  —  local  conditions 
affecting  frost,  236  —  conditions  indicating  frost  in  Cali- 
fornia, 237  —  how  plants  are  injured  by  cold,  239  —pre- 
vention of  frost  injury,  243  —  orchard  heating  with  oil, 
252  —  requirements  of  orchard  heaters,  253  —  types  of 
oil  heaters,  257  —  installation  of  heaters,  259  —  proper- 
ties of  fuel  oils,  260  — storage  for  oil,  262 — oil  heating 
operations,  264  —  care  of  heaters,  267  —  cost  of  oil  heat- 
ing, 268  —  separation  of  frosted  from  sound  fruit,  270  — 
cooperation  in  frost  fighting,  274 

CHAPTER   XV 

Picking  and  Packing  Oranges 277-301 

Importance  of  careful  handling,  277— causes  of  decays, 
278  — clippers,  279  — picking  bags,   280  — methods  of 


Contents  xi 


PAGES 


picking,  281  —  the  sweating  of  green  fruit,  285  —  the 
acid-sugar  ratio,  289— brushing  and  washing,  291  — 
grading  and  sizing,  292  —  packing  and  loading,  295  — 
precooling,  297  —  shipping,  298 


CHAPTER   XVI 

Picking  and  Packing  Lemons 302-317 

Season  of  maturity,  303  —  market  demands,  302  — 
sweating  autumn  lemons,  305  —  storage  of  winter  lemons, 
30(5  —  packing  and  shipping,  309  —  grading  and  sizing, 
310  —  picking  pomelos  and  tangerines,  312  —  packing- 
houses, 314 

CHAPTER  XVII 
Blemishes  of  the  Frdit  and  their  Prevention  .  .  318-330 
Insect  blemishes,  319  —  fungus  blemishes,  319  —  me- 
chanical blemishes,  321  —  bruises,  321  —  thorn-stabs, 
321  —  cultivator  scars,  321  —  clipper  cuts,  321 — stem 
punctures,  321 — machine  injuries,  322  —  fumigation 
scars,  322  —  shoulder  spots,  323  —  hail  scars,  323  —  soil 
scars,  323  —  windfalls,  324  —  cement  dust,  324  —  physi- 
ological blemishes,  324  —  sunburn,  324 — frost,  325  — 
off-bloom,  325  —  mottled-leaf,  325  —  exanthema,  325  — 
malformations,  326  —  brown  spot,  326  —  splits  and 
cracks,  326  —  pufiBng,  329  —  peteca,  329  —  dry  center  of 
lemon,  329 

CHAPTER   XVIII 
By-products  ....  ....     331-343 

United  States  importations  of  citrus  by-products,  332 

—  commercial    by-products,   333  —  citric   acid,   333  — 
lemon  and  other  oils,  334  —  unfermented  orange  juice,  335 

—  orange  vinegar,  336  —  orange  wine,   3-37  —  candied 
citron,  337  —  oil  of  neroli,  338  —  petit  grain  oil,  338  — 


Contents 


tincture  of  orange  flowers,  338  —  essence  of  orange 
flowers,  338  —  dried  and  candied  peel,  339  —  lime  juice, 
339  —  orange  paste,  340  —  crystallized  baby  oranges,  340 

—  glaced  kumquats,341  —  domestic  recipes,  341  —  orange 
or  lemon  jelly,  341  —  orange  manualade,  342  —  pomelo 
marmalade,  342  —  citrus-rhubarb  marmalade,  343 

CHAPTER   XIX 
Marketing    .         , 344-364 

Methods  of  selling  fruit,  344 — independent  growers, 
344  —  independent  associations,  345  —  California  Fruit 
Growers'  Exchange,  345  —  the  local  association,  346  — 
the  district  exchange,  347  —  the  central  exchange,  348  — 
collecting  and  handling  money,  350  —  exchange  adver- 
tising, 351  —  method  of  organizing  cooperation  associa- 
tions, 351  —  Florida  Citrus  Exchange,  353  —  Citrus  Pro- 
tective League  of  California,  353 

CHAPTER   XX 

Profit  and  Loss 355-363 

Average  returns,  355  —  over-capitalization,  356  — 
eight  requirements  for  success,  357  —  capital  reciuired, 
358  — cultural  costs  itemized,  361  — average  yields,  362 

—  average  prices  received,  362 — judging  orchards  and 
lands,  362  —  score-card  for  citrus  land,  363 

CHAPTER   XXI 

Diseases  and  their  Controi 364-402 

Brown  rot  gum  disease,  3(i4  —  botrytis  gumming,  .'JOfi 

—  scaly-bark,  367  —  twig  gumming,  367  —  leaf  gumming, 
368 — gumming  of  seed-bed  stock,  368  —  exanthema  or 
die-back,  369  —  mal-di-gomma  or  foot-rot,  372  —  toad- 
stool root-rot,  373  —  mottled-leaf,  374  —  wither-tip,  380 


Contents 


—  twig  blight,  382  —  cottony  mold,  383  —  brown  rot 
fruit  decay,  386  —  blue  mold  and  green  mold,  387  —  gray 
mold,  388  —  black  rot  of  Navel  orange,  388  —  brown 
spot,  389  — damping  off,  391— citrus  canker,  392  — 
melanose  and  stem  end  rot,  394  —  nail-head  rust,  395  — 
scab  or  verrucosis,  395  —  diplodia  rot  of  oranges,  397 

—  red  blotch  of  lemon,  398  —  yellow  spotting  of  oranges, 
398  — stem  end  spot,  399  —  trunk  rot,  399  —  galls  and 
knots,  401  —  black  pit  of  lemons,  401 

CHAPTER   XXII 

CiTULS  Insects  and  their  Control   403-430 

Black  scale,  405  —  red  or  orange  scale,  411  —  yellow 
scale,  414  —  purple  scale,  414  —  cottony  cushion  scale, 
417 — soft  brown  scale,  418 — citricola  scale,  419  — 
hemispherical  scale,  420  —  greedy  scale,  420  —  oleander 
scale,  420  —  citrus  mealybug,  421  —  citrus  red  spiders, 
423  —  silver  mite,  424  —  orange  thrips,  425  —  aphis  or 
plant  louse,  427  —  orange  tortrix,  428  —  Fuller's  rose 
beetle,  429  —  western  twelve-spotted  cucumber  beetle, 
430 

CHAPTER   XXIII 

Insect  Control  by  Fumigation 431-452 

History  of  fumigation,  431  —  fumigation  by  hydro- 
cyanic acid  gas,  435  —  tents,  435  —  equipment  of  tents, 
437  —generators,  437  — cyanide,  438— acid,  439 — oper- 
ation, 440  —  season  of  fumigation,  443  —  dosages,  449  — 
dosage  schedule  for  sodium  cyanide,  446  —  new  Wood- 
worth  dosage  table,  450  — cost  of  fumigation,  452 


CHAPTER   XXIV 
Various  Orchard  Pests  and  their  Control  . 

Citrus   nematode,    453  —  the  pocket  gopher, 
ground  squirrels,  458  —  poisons,  459 


456- 


453-459 


xiv  Contents 


CHAPTER   XXV 

PAGES 
$IBLIOGRAPHY 460-503 

Other  bibliographies,  4(51  —  references  to  literature 
dealing  with  particular  fruits,  4(51  —  orange  giowing  in 
United  States,  461  —  growing  in  other  countries,  463  — 
varieties,  464  —  breeding,  467  —  insects,  467 — diseases, 
468  —  lemon,  460 — lime,  471  —  mandarin,  471  — 
pomelo,  472  —  kumquat,  471  —  citron,  473 — references 
to  literature  dealing  with  citrus  fruits  in  general,  473  — 
miscellaneous  references,  473  —  propagation,  stocks, 
scions,  478  —  breeding,  470 — soils,  roots,  481  —  irriga- 
tion, 482  —  fertilization,  483  —  cover-crops  and  green 
manuring,  484  —  varieties,  botany,  485  —  chemistry, 
judging,  486  —  pruning,  487  —  curing,  storing,  sweating, 
packing,  480  —  marketing,  organization,  statistics,  tariff, 
400  —  by-products,  402  —  frost  fighting,  frost  injured 
fruit,  45)4  —  insect  pests,  496  —  fumigation,  497  — 
diseases,  499 


LIST   OF   ILLUSTRATIONS 


Washington  Navel  orange Frontispiece 

Flli.  PAGE 

1.  Thomas  A.  Garey,  a  pioneer  citrus  nurseryman    ...  4 

2.  The  passing  of  the  old  seedling  orange  groves       .         .        .12 
;>.    Mrs.  L.  C.  Tibbet,  who  first  brought  the  true  Navel  orange 

to  California 18 

4.  One  of  the  two  original   Washington   Navel  orange  trees 

brought  to  California 21 

5.  California  citrus  areas 27 

6.  Four-year-old  Valencia  orange  grove  in  Los  Angeles  County  28 

7.  Typical  scene  in  Los  Angeles  County.     Windbreak  of  Gre- 

villea  robiista  on  right 35 

8.  Finns  radiata,  a  native  pine,  used  as  a  windbreak        .        .  36 

9.  Orange  tree  denuded  of  foliage  on  windward  side  by  three 

days  of  desert  wind 37 

10.  Growth  rings  in  a  flattened  brace-limb  of  lemon    ...  47 

11.  Result  of  experiment  which  shows  that  a  girdled  orange  tree 

may  grow  new  bark.     A.  Untreated ;  B.  Treated          .  48 

12.  Valencia  orange  blossoms 53 

13.  Lemon  blossoms  showing  perfect,  partly  aborted  and  aborted 

pistils.     Stamens  removed  in  latter  case          ...  54 

14.  Orange  flower  x  2.    p,  pistil  ;  a,  stigma  ;  c,  style  ;  o,  ovary  ; 

s,  stamen  ;  b,  anther  ;  e,  filament ;  d,  nectary  ;  g,  sepal  ; 

/,  petal 57 

15.  Polyembryony.     Two  orange  seedlings  from  one  seed  .         .  60 
10.   The  earliest  known  illustration  of  a  Navel  orange.     From 

Ferrarius'  "  Hesperides,"  1040 67 

17.  One  type  of  Australian  Navel  orange 69 

18.  Eureka  lemon,  uncured 73 

19.  Lisbon  lemon,  uncured 75 

XV 


xvi  Li.si  of  Illustrations 

FIG.  PAGE 

20.  Seedless   pomelo,    flowers   and    fruit.     From    Volckamer's 

"  Ilesperides,"  1708 70 

21.  Dancy  Mandarin  orange 78 

22.  Satsuma  Mandarin  orange 80 

23.  Nagami  kumquat 82 

24.  Citrus  seed-bed  under  lath 85 

26.    Citrus  seed-bed  in  the  open 89 

26.  Bench-rooted  orange  seedling 90 

27.  Orange  bud-wood 98 

28.  Cutting  a  bud 96 

29.  Making  incision  in  stock 97 

30.  Inserting  bud 98 

31.  Tying  inserted  bud 99 

32.  Orange  buds  in  nursery  row  tied  to  lath  stakes      .         .         .  101 

33.  Healing  of  the  bud  union 103 

34.  Balling  orange  trees  in  the  nursery 104 

35.  A  shipment  of  defoliated  balled  orange  trees          .         .         .  108 

36.  Two-year-old  orange  trees,  balled,  ready  for  market     .         .112 

37.  Type  of  standard  Washington  Navel  orange  .         .         .         .117 

38.  Washington  Navel  oranges  showing  fluctuations  in  the  navel. 

Such  variations  cannot  be  preserved  by  budding    .         .119 

39.  Variegated  sport.    Note  white  areas  in  leaves.    From  Volck- 

amer's "  Hesperides,"  1695 121 

40.  A  variegated  sport  of  Valencia  orange.    Notice  white  margin 

of  leaves 122 

41.  Sectorial  chimera  of  Valencia  orange 124 

42.  Orange  showing  sectorial  chimera.     From  Ferrarius'   "  Hes- 

perides," 1646 126 

43.  What  is  known  as  the  "  Wrinkled"  sport  of  Eureka  lemon 

compared  with  normal  fruit.     Both  from  same  tree        .  127 

44.  Chart  showing  by  dotted  line  the  small  proportion  of  profit- 

able trees,  and  by  heavy  line  the  large  proportion  of 
trees  which  only  pay  for  their  care.     West  Highlands 

Orchard.     (Adapted  from  Norton)          ....  129 

46.    Cow  peas  as  an  intercrop  in  young  lemon  orchard         .         .  153 
46.   Breaking  a  layer  of  hardpan  by  means  of  a  stick  of  dynamite 

discharged  in  each  tree  hole 156 


List  of  Illustrations  xvii 


FIG.  PAGE 

47.  Newly  set  tree  properly  protected  from  sun  ....  158 

48.  Cultivating  newly  set  orange  trees  with  eight-chisel  cultivator  166 

49.  Cloddy  condition  due  to  land  being  worked  while  too  wet    .  167 

50.  Ground  under  trees  worked  with  ease  by  means  of  orchard 

tractor 169 

51.  Orchard  tractor  doing  the  work  of  eight  mules  in  a  hot 

desert  valley 171 

52.  Heavy  plowing  with  an  orchard  tractor  of  the  caterpillar 

type 173 

53.  Substituting  baled  lima  bean  straw  for  manure  in  lemon 

orchard  near  Whittier,  California 176 

54.  Cull  oranges  used  as  a  humus-forming  fertilizer    .         .         .     180 

55.  Canal  lined  with  cement.     Transformation  of  desert  hills 

into  orange  groves 187 

56.  Preparing  the  ground  for  furrow  irrigation.     (From  U.  S. 

D.  A.  Farmers'  Bid.  No.  404) 190 

57.  Irrigating  stands  in  operation 194 

58.  Zigzag  furrows  for  wetting  the  ground  between  the  trees      .  197 

59.  Overhead   irrigation   system   in   old    orange    orchard    near 

Covina,  California 199 

60.  King  soil  sampler.     Of  use  when  irrigating    ....     202 

61.  A   well    pruned    Eureka    lemon   orchard.       Photographed, 

August  10th,  near  Alhambra,  California         .         .         .     205 

62.  Prototype  of   California   pruning  saw.     From  Volckamer's 

"  Hesperides,"  1708 207 

63.  "  California  "  pruning  saw,  used  throughout  southwest         .     208 

64.  Good  type  of  pruning  saw  above  ;  poor  type  below        .         .     210 

65.  One  of  the  best  types  of  pruning  shears  .         .         .         .211 

66.  Vigorous  fruiting  brush  gi-owing  in  the  place  of  suckers         .     212 

67.  This  extra  vigorous  shoot  terminated  at  six  inches  with  a 

fruit  showing  that  excess  of  food  did  not  change  it  into 

a  sucker 214 

68.  A  sixty-acre  three-year-old  Valencia  orchard  top-worked  to 

lemons.       The  paper  bags  protect  the  buds  from  rose 

beetles 215 

69.  Fifteen  months'  growth  on  stocks  shown  at  Fig.  68       .         .  216 

70.  Three-year-old  Navel  head  on  top-worked  sweet  seedling      .  221 


xviii  List  of  Illustrations 

VUi.  I'AGK 

71.  Prunine;  a  frosted  lemon  orchard 222 

72.  A.  Normal  vesicles  of  lemon.     Ji.  Enlarged  vesicles  from 

frosted  fruit  six  months  after  injury      ....  230 

73.  Frost  splitting  of  bark  on  fruiting  brush  of  lemon        .         .  241 

74.  Three-year-old  trees  protected  with  cornstalks     .         .         .  245 
7o.    Screen  of  tobacco  cloth  as  a  frost  protection        .        .         .  246 

76.  Big  six 247 

77.  Eichhoff  coal  burner 248 

78.  Hamilton  down-draught 249 

79.  Bolton  .         • 250 

80.  Coe 251 

81.  Pomona  pipe-line  heater 251 

82.  Dunn 254 

83.  Canco 255 

84.  Kayo 25t) 

85.  Hislop 257 

86.  Hamilton  reservoir 258 

87.  Troutraan 258 

88.  Adamson  torch 25!) 

89.  Coal-burning  orchard  heaters.     Fuel  stored  in  boxes  under 

trees 261 

90.  Orchard  heaters  ready  for  lighting        .                  ...  262 

91.  Orchard  heaters  in  old  Valencia  grove          ....  263 

92.  Placement  of  orchard  heaters.     Extra  fuel  in  cans  under 

trees 265 

93.  The  perforated  stack  gives  good  combustion  but  may  admit 

rainwater 266 

94.  The  water  separator  for  frosted  fruit    .         .                  .         .  271 

95.  Thermometer  station  of  the  Pomona  Valley  Orchard  Pro- 

tective Association 275 

96.  Tuttle  fruit  clippers  with  rounded  points      ....  279 

97.  Dashboard  picking  bag 280 

98.  Co  Vina  picking  bag                281 

99.  Woodward  picking  bag 282 

100.  The   Wiss   clipper   now    being   sajxTseded    by   tin-   'i'uitle 

shown  at  Fig.  96 283 

101.  Metal  attachment  for  propping  up  limbs      ....  283 


List  of  Illustrations  xix 

ri'J.  PAGE 

102.  Worm  brushes  used  for  polishing  oranges    ....  284 

103.  Rope  feed  hopper 285 

104.  Orange  sizing  machine  .         .         .         .         .         .         .  286 

105.  Box  press  and  naiHng  machine     .         .         .         .  •       ,         .  287 

106.  Citrus  fruit  truck 288 

107.  Packing  stand 289 

108.  Box-squeeze,  small  size 290 

109.  Car-squeeze,  large  size 291 

110.  Interior  view  of  the  Pioneer  Fruit  Co.'s  orange  packing 

house  at  Lindsay,  California 294 

111.  Orange  packers  at  work 296 

112.  A  typical  orange  box  label 299 

113.  General  aiTangement  of  orange  packing  house     .         .        .  300 

114.  Picking  lemons 302 

115.  Two-story  lemon  packing  house,  Glendora,  California         .  304 

116.  Lemon  washing  machine  and  sorting  table  ....  307 

117.  Lemon  curing  tents  in  packing  house  near  the  coast    .         .  309 

118.  Truck  for  handling  trays  of  ungraded  lemons       .         .         .  310 

119.  Packing  lemons  from  sorting  trays       .         .         .         .         .311 

120.  Lemon  packing  house,  second  floor  and  elevation        .         .  314 

121.  Typical  lemon  box  label 315 

122.  Combination  box  label 316 

123.  Fumigation  scars 322 

124.  Scar  caused  by  rubbing  on  the  ground          ....  323 

125.  Orange  splits.     Side  splits  above  and  Navel  end  splits  below  327 

126.  Horizontal  cracks  are  very  different  from  splits  .         .         .  328 

127.  Peteca  of  lemon 329 

128.  The  Fawcett  method  of  treating  gum  disease.     Note  types 

of  scrapers 365 

129.  Reddish   gum   areas   on   under  side   of   leaves  caused   by 

sunburn 368 

130.  Exanthema  pustules  on  Valencia  orange  twigs    .         .         .  370 

131.  Mottled-leaf  disease  on  Eureka  lemon  ....  375 

132.  Advanced  stage  of  mottled-leaf  disease  showing  multiple 

buds 377 

133.  Spot  caused  by  wither-tip 380 

134.  A  "  ne.st  "  of  cottony  fungus 384 


XX  List  of  llludrations 

Fl<;.  PACK 

136.  Black  rot  of  Navel 388 

136.  Brown  spot  of  Navel  orange 390 

137.  Stem-end  spot  of  orange 399 

138.  Pruning  stub  on  orange  tree  infected  with  xchizophylhim    .  400 

139.  Black  scale  on  orange  twig 400 

140.  The  red  scale  on  orange 411 

141.  Work  of  red  scale  on  orange  tree 413 

142.  The  purple  scale  enlarged 416 

143.  Cottony  cushion  scale 417 

144.  Citrus  mealy-bug 422 

145.  Scars  due  to  citrus  thrips 426 

146.  Fuller's  rose  beetle 429 

147.  The  work  of  Fuller's  rose  beetle 429 

148.  Scars  on  rind  of  orange  caused  by  katydid  ....  430 

149.  A  fumigation  demonstration 432 

150.  Method  of  marking  fumigating  tent 436 

151.  Flashlight  picture  of  marked  fumigating  tents     .         .         .  442 


CITRUS   FRUITS 


CITRUS  FRUITS 


CHAPTER  I 

HISTORY  AND  DEVELOPMENT  OF  THE  CITRUS 

INDUSTRY  IN  THE  SOUTHWESTERN  UNITED 

STATES 

Citrus  seeds  were  first  brought  into  California  from 
the  peninsula  of  Lower  California,  where  peoples  of  Spanish 
descent  have  cultivated  various  kinds  of  European  fruit 
trees  and  vines  since  the  year  1701.  In  1768  the  Jesuit 
missionaries  were  supplanted  by  the  Franciscans,  some 
of  whom  under  the  leadership  of  Junipero  Serra  pushed 
northward  into  the  territory  which  is  now  the  state  of 
California.  These  hardy  pioneers  founded  the  first 
mission  in  Upper  California  at  San  Diego  in  1769,  and 
proceeding  northward  established  a  chain  of  missions 
extending  four  hundred  miles  along  the  coast,  the  last 
being  established  at  Somoma  in  1823. 

At  a  number  of  these  missions,  vineyards  and  orchards 
were  planted.  Cuttings  of  grapes  and  figs,  and  seeds  of 
oranges,  pomegranates,  citrons,  olives,  pears,  dates,  and 
other  fruits  were  brought  from  the  older  missions  on  the 
peninsula.  At  several  missions  the  remnants  of  the  old 
orchards  may  still  be  seen,  partly  inclosed  by  the  adobe 
walls  which  were  built  to  protect  the  trees  from  wandering 
herds  of  cattle. 

B  1 


2  Citrus  Fruits 

The  San  Gabriel  Mission  near  the  present  city  of  Los 
Angeles,  by  reason  of  the  abundance  of  water  and  the 
large  number  of  neophytes  brought  into  service,  gained 
rapidly  in  wealth  and  productiveness.  The  exact  date 
when  orange  seed  were  first  planted  at  this  mission  is  not 
known,  as  the  archives  of  the  mission  church  are  lost.  It 
is  certain,  however,  that  the  first  California  orange  orchard 
of  any  size  occurred  at  San  Gabriel,  and  various  writers 
agree  that  this  orchard  must  have  been  planted  in  1804 
or  the  following  year.  This  first  orchard  covered  about 
six  acres  of  ground  and  was  composed  of  about  four 
hundred  seedling  trees,  a  few  of  which  were  still  bearing 
in  1885. 

Although  this  orchard  was  not  planted  for  financial 
gain,  and  it  is  doubtful  if  any  fruit  was  ever  sold  from  it, 
the  success  of  this  pioneer  planting  established  the  fact 
that  the  climate  and  soil  conditions  were  quite  favorable 
to  the  production  of  citrus  fruits. 

Soon  orange  trees  distributed  from  the  missions  began 
to  be  planted  in  court-yards  and  gardens  in  various 
places,  the  fruits  being  either  all  consumed  at  home  or 
given  away  to  friends.  Perhaps  the  largest  number  of 
trees  in  any  private  garden  were  the  thirty-five  trees 
transplanted  from  San  Gabriel  about  the  year  1834  to 
Aliso  Street  in  Los  Angeles,  by  Don  Louis  Vignes.  It 
remained,  however,  for  William  Wolfskill,  a  Kentucky 
trapper  of  German  blood,  who  had  come  to  Los  Angeles 
overland  in  1831,  to  forecast  the  commercial  possibilities 
of  this  fruit.  Wolfskill  secured  orange  trees  from  the  San 
Gabriel  Mission  in  1841  and  planted  a  two-acre  orchard 
in  what  is  now  the  city  of  Los  Angeles,  on  the  spot  now 


History  and  Development  of  the  Citrus  Industry       3 

occupied  by  the  Arcade  passenger  station  of  the  SouthgEjii 
Pacific  Railroad.  The  fruit  from  this  orchard  sold  to 
such  advantage  that  it  was  increased  in  size  to  about 
twenty-eight  and  finally  to  seventy  acres.  It  is  said  that 
Wolfskin  was  the  first  to  ship  a  full  car  of  oranges  to 
Eastern  markets.  They  were  sent  to  St.  Louis  in  1877 
and  arrived  in  good  condition  after  having  been  a  month 
in  transit.  The  freight  charge  is  said  to  have  been  $500. 
The  last  crop  disposed  of  in  his  lifetime  sold  on  the  trees 
for  $25,000. 

The  success  of  the  Wolfskill  orchard  stimulated  others, 
and  in  1853  Matthew  Keller  secured  orange  seeds  from 
Central  America  and  also  from  Hawaii.  From  these  he 
raised  young  trees  with  which  he  planted  an  orchard 
opposite  that  of  Wolfskill .  In  1 857  L.  Van  Leuven  planted 
orange  trees  at  Old  San  Bernardino,  and  in  the  same 
year  L.  F.  Cram  planted  a  small  orchard  at  Highlands. 
Myron  H.  Crafts  planted  two  hundred  orange  trees  at 
Crafton  in  1865. 

In  September,  1870,  J.  W.  North  of  Knoxville,  Ten- 
nessee, bought  four  thousand  acres  of  desert  land  which 
is  now  occupied  by  the  city  of  Riverside.  Judge  North 
carried  on  an  advertising  campaign  in  the  Eastern  states 
to  attract  colonists  to  this  land.  Settlers  began  to  arrive 
the  following  winter,  and  in  the  spring  of  1871  the  first 
orange  seeds  were  planted. 

This  means  of  settling  the  country  was  used  in  various 
parts  of  California.  Pasadena  was  first  known  as  the 
Indiana  Colony,  the  lands  being  purchased  in  1873, 
distributed  in  1874,  and  orange  orchards  planted  as  soon 
as  the  ground  was  leveled  and  irrigation  water  provided. 


Citrus  Fruits 


Frank  A.   Kimball  planted  orange  and  lemon  trees  at 
National  City  in  San  Diego  County  about  1870. 

A  large  proportion  of  the  trees  planted  at  this  time  were 
purchased  from  the  nursery  of  T.  A.  Garey  in  Los  Angeles 
(Fig.   1).      Garey  imported  a  large  number  of  varieties 

from  various  places 
during  the  years  1868 
to  1875.  He  is  said 
to  have  received 
shipments  of  trees 
from  Australia, 
southern  Europe,  and 
Florida,  as  well  as 
from  the  nurseries  of 
Ellwanger  and  Barry 
of  Rochester,  N,  Y., 
and  Sir  Thomas 
Rivers  of  Sawbridge- 
worth,  England. 

The  fruit  from 
these  primitive  or- 
chards was  either 
consumed  in  the 
neighborhood  of  its 
production  or  hauled 
to  Los  Angeles  and  there  shipped  to  northern  ports  by 
water.  Southern  California  still  lacked  railroad  connec- 
tion with  the  Eastern  markets  and  there  was  no  incentive 
to  grow  more  oranges  than  sufficed  for  local  consumption. 
Orange  trees  were  first  planted  in  the  central  and 
northern  part  of  California  in  the  early  sixties.     The  first 


1.  —  Thomas    A.    Garey, 
citrus  nurseryman. 


History  and  Development  of  the  Citrus  Industry       5 

planting  of  which  we  have  record  was  at  Bidwell  in  Butte 
County  in  1859.  In  a  great  many  cases  these  early 
plantings  proved  successful,  and  it  w^as  soon  apparent 
that  areas  of  greater  or  less  extent,  suitable  for  the 
growth  of  citrus  fruits,  existed  in  many  scattered  locations 
all  the  way  from  San  Diego  in  the  south  to  Shasta  County 
in  the  north. 

The  commercial  development  of  citrus  culture  may  be 
said  to  have  begun  with  the  completion  of  the  Southern 
Pacific  Railroad's  connections  w^ith  the  East.  The  Valley 
line  w^as  completed  in  1876  and  the  Southern  line  to  New 
Orleans  in  1881.  The  exhibition  of  the  first  fruits  of  the 
Washington  Navel  orange  at  Riverside  gave  another 
impetus  to  citrus  planting,  but  the  greatest  development 
came  with  the  completion  of  the  Santa  Fe's  competing 
line  of  railroad,  which  was  opened  up  about  1885.  The 
first  special  train  loaded  exclusively  with  oranges  left  the 
River  Station,  Los  Angeles,  February  14,  1886,  for  the 
East  via  the  Southern  Pacific  and  Union  Pacific  Rail- 
roads. 

In  February  ,1879,  what  was  probably  the  first  of  a  series 
of  annual  citrus  fairs  was  held  at  Riverside.  The  differ- 
ent citrus-growing  communities  of  southern  California 
took  great  interest  in  these  fairs,  and  the  prizes  together 
with  the  prestige  which  they  carried  were  vigorously 
competed  for.  It  was  at  these  early  citrus  fairs  that  the 
great  superiority  of  the  Washington  Navel  orange,  the 
history  of  which  is  given  on  another  page,  became  appar- 
ent. The  climate  and  soil  conditions  in  California  proved 
eminently  suited  to  this  variety  of  orange,  which  here  at- 
tained a  perfection  truly  marvelous.     The  strong  demand 


6  CHrm  Frnitu 

for  these  oninges  in  the  Eastern  markets  and  the  liigh 
priees  reeeived  by  some  brought  on  a  period  of  frenzied 
phmting  and  specuhition.  A  great  deal  of  worthless  nurs- 
ery stock,  quickly  and  cheaply  grown  on  Chinese  lemon 
roots,  w^as  planted,  and  many  orchards  were  set  out  on 
lands  more  or  less  unsuited  to  citrus  culture.  This  wave 
of  rapid  expansion  culminated  in  1885-86,  when  drouth, 
frosts,  scale  insects,  and  the  lack  of  a  coherent  marketing 
organization  conspired  to  rudely  awaken  from  their 
golden  dreams  many  who  had  rushed  into  the  business  with 
insufficient  knowledge  and  capital  to  weather  a  period  of 
depression. 

In  1884,  at  the  Cotton  Exposition  held  in  New  Orleans, 
the  twenty  varieties  of  oranges  grown  and  exhibited  by 
Riverside  took  first  premium  in  competition  with  the 
world.  This  fact  was  heralded  far  and  wide  and  proved 
of  great  value  in  advertising  the  California  citrus  business 
in  general  and  Riverside  in  particular. 

In  the  early  days  of  the  industry  there  was  no  adequate 
horticultural  inspection  or  quarantine  service,  and  as  a 
consequence  a  number  of  kinds  of  very  destructive  scale 
insect  pests  were  introduced  on  nursery  stock  imported 
from  various  parts  of  the  world.  In  this  way  the  cottony 
cushion  scale  (Icerya  jmrchasi)  was  introduced  from 
Australia  in  1868.  In  twenty  years  this  scale  spread 
throughout  the  orchards  of  Los  Angeles  County.  So 
serious  was  this  pest  that  the  industry,  in  Los  Angeles 
County  at  least,  was  on  the  verge  of  extinction. 

In  the  spring  of  1888  Albert  Koebele  was  sent  to  Aus- 
tralia by  the  U.  S.  Department  of  Agriculture  to  study 
the  cottonv  cushion  scale  in  its  native  land.     The  follow- 


History  and  Development  of  the  Citrus  Industry       7 

ing  year  Koebele  succeeded  in  introducing  the  Novius 
cardinalis,  a  small  predaceous  ladybird  beetle,  which  at 
once  attacked  the  scale  and  preyed  upon  it  to  such  an 
extent  that  it  was  checked  in  its  spread,  and  in  many 
localities  it  was  almost  exterminated.  As  a  consequence, 
in  1891 ,  the  shipments  from  Los  Angeles  County  suddenly 
increased  from  7S1  to  2212  cars,  a  net  gain  of  1431  cars, 
due,  at  least  in  large  part,  to  the  good  work  of  the 
ladybird.  Since  the  introduction  of  this  predaceous 
beetle  the  white  scale  has  been  held  in  check  and  is  not 
now  feared  by  citrus  growers. 

The  fight  with  the  cottony  cushion  scale  had  hardly 
been  won,  however,  when  other  difficulties  appeared.  Al- 
though the  orchards  produced  large  crops  it  became  more 
and  more  difficult  to  successfully  market  the  fruit.  The 
season  of  1892-93  was  particularly  disastrous  as  far  as 
net  returns  were  concerned.  The  growers  were  not 
organized,  and  as  long  as  each  grower  attempted  to  market 
his  own  fruit  he  became  an  easy  prey  to  the  miscellaneous 
assortment  of  commission  men,  agents,  and  speculators 
who  at  that  time  infested  the  markets  and  who  in  many 
cases,  it  is  said,  secured  secret  rebates  from  the  railroads. 
In  Riverside  and  in  all  the  older  sections,  where  there  was 
any  quantity  of  fruit  to  ship,  account  sales  in  "red  ink" 
were  received  without  number,  and  it  frequently  happened 
that  the  larger  crop  a  grower  had,  the  more  he  was  in- 
debted to  his  packer  at  the  end  of  the  season.  As  a  result 
of  these  failures  to  successfully  market  large  crops,  a  few 
of  the  growers  began  to  associate  themselves  together  for 
mutual  protection  and  to  provide  better  packing  facilities. 
Stimulated  by  the  success  of  some  of  these  associations  in 


8  Citrus  Fruits 

gainiiifj  concessions  from  the  railroads  and  in  many  otliet 
ways  securing  better  returns  for  their  members,  a  hirge 
percentage  of  the  growers  assembled  at  the  Chamber  of 
Commerce  in  Los  Angeles  on  April  4th,  1(S93,  the  declared 
purpose  of  the  meeting  being :  "To  jjrovide  for  the  mar- 
keting of  all  the  citrus  fruit  at  the  lowest  possible  cost 
under  uniform  methods,  and  in  a  manner  to  secure  to 
each  grower  the  certain  marketing  of  his  fruit  and  the 
full  average  price  to  be  obtained  in  the  market  for  the 
entire  season."  At  this  meeting  a  cooperative  packing 
and  marketing  organization  w^as  formed,  which,  while 
not  entirely  satisfactory,  was  a  great  improvement  over 
the  old  methods  and  served  to  prepare  the  way  for  the 
Southern  California  Fruit  Exchange,  which  was  organized 
October  21,  1895.  At  first  the  Plxchange  handled  about 
32  per  cent  of  the  total  shipments,  but  the  proportion 
of  the  crop  handled  has  gradually  increased  till  at  the 
present  time  the  Exchange  ships  about  62  per  cent  of  the 
total  crop. 

On  ]March  27,  1905,  the  California  Fruit  Growers' 
Exchange  was  incorporated,  and  on  September  1,  follow- 
ing, succeeded  to  the  business  of  the  Southern  California 
Fruit  Exchange,  this  change  in  name  being  deemed 
advisable  in  order  that  the  marketing  organization  itself 
might  in  name  as  well  as  in  fact  become  general  through- 
out the  state  rather  than  remain  local  to  southern  Cali- 
fornia. The  Exchange  is  now  an  association  of  three  groups 
or  classes  of  organizations :  the  one  hundred  and  fifteen 
local  associations ;  the  seventeen  district  exchanges ; 
and  the  central  exchange.  For  a  detailed  description 
of  this  rather  complex  organization  see  pages  345  to  353. 


History  and  Development  of  the  Citrus  Industry       9 


California  Citrus  Shipments 


Season 

Cabloads 

Season 

Carloads 

Season 

.  Carloads 

1890-91 

4016 

1898-99 

10875 

1906-07 

29820 

1891-92 

4400 

1899-00 

18400 

1907-08 

32729 

1892-93 

5871 

1900-01 

24900 

1908-09 

40592 

1893-94 

5022 

1901-02 

19180 

1909-10 

32648 

1894-95 

7575 

1902-03 

23871 

1910-11 

46394 

1895-96 

6915 

1903-04 

29399 

1911-12 

40673 

1896-97 

7350 

1904-05 

31422 

1912-13 

18960 

1897-98 

15400 

1905-06 

27610 

1913-14 

48548 

Not  the  least  important  factor  in  building  up  the  citrus 
industry  has  been  the  protective  duties  imposed  upon 
citrus  imports  by  the  Congress  of  the  United  States.  Such 
protective  duties  have  prevailed  since  July  4,  1789,  when 
a  general  tariflf  bill  was  passed  which  included  a  5  per  cent 
ad  valorem  duty  on  all  citrus  fruits.  Since  that  time  the 
duty  has  been  gradually,  though  not  uniformly,  increased 
by  the  enactment  at  different  times  of  nineteen  changes 
in  the  law.  By  the  Underwood-Simmons  tariff  act,  effective 
October  4,  1913,  the  duty  is  one-half  cent  per  pound  on 
oranges,  lemons,  pomelos,  and  limes.  Orange  peel  or 
lemon  peel,  preserved,  candied,  or  dried,  one  cent  per 
pound  ;  citron  or  citron  peel,  preserved,  candied,  or  dried, 
two  cents  per  pound.  Citric  acid,  five  cents  per  pound. 
Citrate  of  lime,  one  cent  per  pound.  Orange  and  lemon 
oil,  ten  per  cent  ad  valorem.  Bergamot,  neroli,  or 
orange  flower  oil,  twenty  per  cent  ad  valorem.  The 
free  list  includes  fruits  in  brine ;  lemon,  lime,  and  sour 
orange  juice  containing  not  more  than  two  per  cent  of 


10  Citrus  Fruits 

alcohol ;  and  orange  and  lemon  peel  not  preserved,  can- 
died, or  dried. 

California  citrus  culture,  among  all  horticultural  in- 
dustries, is  peculiar  in  that  the  people  who  have  built 
it  up  have  been,  in  many  cases,  retired  business  men  or 
professional  men  from  the  New  England  and  Central 
states.  Persons  who  have  lost  their  health  in  the  process 
of  gaining  wealth  have  bought  and  developed  citrus 
proj^erties,  the  management  of  which,  by  requiring  a  life 
in  the  open  sunshine  and  dry  air,  has  resulted  in  renewed 
health  and  steadied  nerves.  These  people  brought  to 
the  industry  much  needed  capital,  commercial  habits, 
and  business  ability.  Citrus  culture  appeals  to  people 
of  intelligence  and  refinement,  and  such  are  being  drawn 
from  many  occupations.  Now  since  the  automobile 
has  come  into  such  general  use,  the  wealthy  business  man 
of  the  city  builds  a  residence  in  his  orange  orchard  in  the 
suburbs,  while  along  the  interurban  electric  lines  may  be 
found  the  small  orchards  of  the  superannuated  minister, 
the  retired  high  school  teacher,  the  lawyer,  the  doctor, 
as  well  as  of  those  drawn  from  other  walks  of  life. 

The  result  of  this  has  been  the  development  of  an  in- 
dustry characteristically  American  in  spirit  and  new  in 
methods.  The  sons  and  grandsons  of  pioneers  from  the 
West  and  middle  West  have  little  regard  for  the  precedents 
and  practices  of  the  Old  World  citrus-producing  regions. 
European  methods  are  practically  ignored  in  systems  of 
cultivation,  irrigation,  and  pruning.  In  their  readiness 
to  organize  among  themselves  along  business  lines  and 
work  together  for  the  better  picking,  packing,  and  mar- 
keting  of   the    fruit,   the    CaHfornia   citrus  growers  are 


History  and  Development  of  the  Citrus  Industry     11 

probably  in  advance  of  any  other  class  of  fruit  growers 
on  earth. 

The  citrus  industry  has  also  been  greatly  benefited  by 
various  government  agencies,  whose  endeavor  has  been  to 
increase  knowledge  through  scientific  investigations  and 
disseminate  this  new  information  through  free  lectures 
and  pamphlets,  by  experiment  farms,  and  by  operating 
for  months  at  a  time  free  demonstration  trains  on  the 
railroads.  There  have  been  three  principal  agencies 
engaged  in  this  work :  the  University  of  California  Agri- 
cultural Experiment  Station,  the  United  States  Depart- 
ment of  Agriculture,  and  the  State  Horticultural  Com- 
mission. The  university  work  may  be  said  to  have  begun 
with  the  analyses  of  oranges  and  lemons  in  1885  and  con- 
tinued to  date,  covering  a  multitude  of  problems  affecting 
the  industry.  The  university  conducts  a  special  corre- 
spondence course  on  citrus  fruits  for  the  benefit  of  growers 
everywhere.  The  agents  of  the  Department  of  Agricul- 
ture have  rendered  valuable  service  to  the  industry  in 
many  ways.  The  State  Commission  of  Horticulture  has 
done  much  good  work  in  preventing  the  entrance  into  the 
state  of  new  pests  and  checking  the  spread  of  pests  al- 
ready introduced.  It  has  distributed  many  valuable 
publications,  the  one  prepared  by  Lelong  ^  in  1902  being 
of  special  value  to  the  industry. 

A  large  number  of  strong,  loyal  agricultural  and  horti- 
cultural periodicals  throughout  the  state  have  broad- 
casted useful  information  and  fanned  the  flame  of  popular 
interest. 

Still  another  upbuilding  agency  has  been  the  Chambers 

1  B.  M.  Lelong,  "Culture  of  the  Citrus  in  California,"  1902. 


12 


Citrus  Fruits 


of  Commerce  in  the  various  towns  and  cities.  By  main- 
taining interesting  and  attractive  exhibits  with  free  stereop- 
ticon  lectures  for  visitors  and  tourists,  and  by  preparing 
large  exhibits  for  distant  expositions,  they  have  done  a 
great  deal  to  advertise  the  industry. 

Citrus  culture  in  California  will  always  be  a  popular 

occupation  be- 
cause it  appeals 
to  a  man  from 
so  many  sides. 
It  appeals  to 
his  love  of  the 
beautiful ;  beck- 
ons him  to  health- 
ful outdoor  life ; 
stimulates  that 
inborn  desire  in 
man  to  make 
things  grow ;  sat- 
isfies his  appetite, 
and  last,  but  by 
no  means  least, 
it  tempts  him 
with  offers  of  large 
financial  rewards.  Successful  citrus  culture  calls  for  a 
combination  of  the  science  and  the  art  of  horticulture ; 
requiring  both  skill  and  industry,  it  gives  healthful  occu- 
pation to  the  mind  as  well  as  the*body.  While  a  good 
many  seedling  orchards  still  persist  in  the  older  sections, 
they  are  gradually  yielding  (Fig.  2)  to  the  activities  of 
the  woodchopper. 


Fig.   2. 


•The    passing    of    the    old    seedling 
orange  groves. 


History  and  Development  of  the  Citrus  Industry     13 


HISTORY   OF   THE    WASHINGTON   NAVEL    OR    B.IHIA   ORANGE 

The  earliest  illustrated  description  of  a  Navel  orange 
on  record  was  published  in  Rome  by  a  monk  of  the  Society 
of  Jesus,  John  Baptiste  Ferrarius,  in  1646,  in  one  of  four 
books  called  "The  Hesperides  or  About  the  Golden  Apples, 
Their  Culture  and  Use."  The  picture  reproduced  on  page 
52  of  Lelong's  "Culture  of  the  Citrus  in  California," 
from  John  Johnson's  book,  will  be  seen  on  close  comparison 
to  be  an  artful  copy  from  Ferrarius.  This  was  certainly 
not  the  Washington  Navel  as  we  have  it  to-day,  but 
merely  one  of  the  many  Navel  forms  which  have  ap- 
peared from  time  to  time.  It  is  not  unlikely  that  still 
other  kinds  of  Navels  will  appear  in  the  future. 

Orange  trees  were  taken  to  Brazil  by  the  Spaniards 
at  a  very  early  day  and  were  more  or  less  widely  planted 
in  those  parts  of  the  country  best  suited  to  their  culture. 
Some  time  about  the  year  1820  or  possibly  earlier  there 
appeared  near  the  village  of  Bahia  a  form  of  Navel  orange 
which  was  remarkable  for  its  many  good  qualities.  This 
was  what  we  now  know  as  the  Washington  Navel.  It  was 
hastily  propagated  and  planted  to  a  considerable  extent. 
Specimens  were  sent  to  London  and  the  form  became 
known  abroad  under  the  name  Bahia,  after  the  village  where 
it  originated.  At  Bahia  it  was  called  simply  "  Lavanja  de 
Umbigo.'^ 

Circumstantial  evidence  from  several  directions  all 
points  to  the  probability  that  from  the  very  beginning 
one  characteristic  of  this  Navel  orange  was  to  produce 
occasional  branches  which  bore  fruit  differing  from  that 
of  the  rest  of  the  tree.     In  this  wav  a  modified  form  came 


14  Citrus  Fruits 

into  existence,  the  fruit  of  which  was  scant  in  amount, 
large  in  size,  with  a  coarse  exterior,  and  interior  full  of 
rag.  Unwittingly  this  form  was  propagated  along  with 
the  true  Bahia.  After  years  of  experience  the  best  Brazil- 
ian growers  became  aware  of  this  sporting  habit  and 
were  careful  to  select  buds  for  propagation  from  the  best 
type  only.  The  peasants,  however,  did  not  comprehend 
tjje  situation,  and  as  the  demand  increased,  continued  to 
cut  bud  wood  indiscriminately.  On  account  of  the  pub- 
licity given  the  fruit  sent  to  London,  a  trade  in  nursery 
trees  sprang  up.  Agents  from  Rio  de  Janeiro  went  to 
Bahia  and  secured  what  was  available,  including  both 
the  prototype  and  the  false  type.  Thus  it  is  natural  to 
suppose  that  the  stock  on  the  Rio  de  Janeiro  market 
must  have  consisted  of  some  lots  of  Bahia,  some  of  false 
Bahia,  and  some  mixed  lots. 

There  is  a  tradition  that  this  Bahia  Navel  was  intro- 
duced into  Florida  some  time  previous  to  1835,  but  that 
the  trees  were  killed  in  the  freeze  of  that  year.  It  is  said 
that  the  Bahia  Navel  was  introduced  into  Cape  Colony, 
South  Africa,  by  a  Mr.  Brehm  of  Uitenhage  about  1840. 
The  subsequent  record  of  these  trees  shows  that  Brehm 's 
importation  consisted  entirely  of  the  false  form.  On  this 
account  the  Bahia  was  held  in  ill  repute  in  South  Africa, 
until  between  1894  and  1900,  when  a  number  of  importa- 
tions of  the  true  Bahia  were  made  direct  from  California. 
The  fruit  of  these  has  been  found  equal  in  every  respect 
to  the  best  California  product,  and  most  of  the  old  orchards 
have  now  been  budded  over. 

From  Brazil  the  Sweet  orange  was  first  introduced  into 
New  South  Wales,  Australia,  by  Captain  Hunter,  who  ac- 


History  and  Development  of  the  Citrus  Industry     15 

companied  Gen.  Arthur  Phillip  at  the  founding  of  the 
colony  in  1788. 

Orange  growers  in  Australia  early  introduced  the  Bahia 
Navel  direct  from  Brazil.  One  writer  in  1858  states 
that  Navel  oranges  were  for  sale  in  Australian  markets, 
and  that  they  brought  a  much  higher  price  than  other 
varieties.  I  have  been  unable  to  discover  the  exact  date 
of  introduction,  but  oranges  were  exported  in  consideralDle 
amounts  from  New  South  Wales  in  1860,  and  it  is  perhaps 
safe  to  assume  that  at  least  a  part  of  these  were  Bahias, 
since  a  writer  in  the  Victorian  Farmer's  Journal  in  1862 
states  that  on  account  of  the  high  prices  received,  the 
"Bahia  Navel"  was  largely  grown.  From  these  state- 
ments it  would  seem  that  the  date  of  the  introduction  of 
the  Navel  into  Australia  should  be  given  as  not  later  than 
1850.  Australian  writers  are  not  unanimous  in  praise  of 
the  Navel  and  this  indicates  that  both  the  true  and  the 
false  form  existed  there  as  early  as  1860.  We  may  con- 
clude, therefore,  that  this  orange  was  grown  commercially 
and  was  marketed  under  the  name  of  Bahia  or  Navel 
orange  as  early  as  1860. 

S.  B.  Parsons,  a  nurseryman  of  Flushing,  Long  Island, 
owned  a  small  nursery  at  Blue  Spring,  Florida.  Wishing 
to  secure  this  Bahia  Navel  for  propagation  and  sale,  he 
ordered  trees  in  1868  from  Thomas  Rivers,  a  large  nurs- 
eryman of  Sawbridgeworth,  England,  who  had  received 
his  stock  from  the  Azores,  to  which  place  they  were  said 
to  have  been  brought  from  Brazil.  (In  all  probability 
they  were  not.)  This  orange  proved  not  to  be  the  Bahia 
Navel,  and  has  since  been  known  as  the  Parsons  Navel. 
Thomas  Rivers  also  sold  some  of  the  same  lot  of  trees  to 


16  Citrus  Fruits 

A.  B.  Chapman  of  San  Gabriel,  California,  in  1870  or  1871. 
Some  of  these  were  propagated  and  sold  by  Mr.  Chapman 
as  the  Rivers  Navel. 

Thomas  A.  Garey,  a  well-known  California  nurseryman 
and  author  of  a  book  on  orange  culture,^  established  a 
citrus  nursery  in  Los  Angeles  in  1865.  Some  of  his  asso- 
ciates now  living  inform  me  that  he  imported  citrus  seeds 
and  trees  from  Australia,  Mexico,  Central  America,  and 
southern  Europe.  He  is  said  to  have  secured  the  Navel 
in  1870,  and  it  is  an  open  question  as  to  where  he  got  it, 
with  the  probability  strongly  in  favor  of  Australia.  I 
have  a  copy  of  his  catalogue  dated  1876,  in  which  he  lists 
it  as  "  Bahia  Navel, "  but  cautions  his  customers  against 
its  shy  bearing.  Some  persons  who  bought  trees  from 
him  at  that  time  condemn  them  as  worthless,  while  others 
claim  that  they  were  identical  with  the  Washington  Navel. 
Garey  must  certainly  have  secured  at  least  a  preponder- 
ance of  the  false  type  of  Navel.  In  1873  J.  C.  Wallace 
of  Los  Angeles  imported  four  Navel  trees  from  Australia, 
all  of  which  proved  to  be  the  false  form  and  have  been 
budded  over.  From  this  time  this  false  form  of  Bahia 
Navel  became  known  in  California  as  the  "Australian 
Navel"  to  distinguish  it  from  the  true  Bahia.  The 
Parsons  Navel  trees  distributed  by  A.  B.  Chapman  under 
the  name  of  Rivers  Navel  also  came  to  be  known  as 
Australians.  In  fact,  any  forms  which  differed  from  the 
true  Bahia  of  the  "Tibbet"  tree  type  were  very  likely  to 
be  called  Australians,  and  on  account  of  this  name  they 
were  supposed  by  many  to  have  originated  in  Australia. 

1  "Orange  Culture  in  California,"  by  T.  A.  Garey,  San  Fran- 
cisco, 1882. 


History  and  Development  of  the  Citrus  hidiistry 


17 


I  can  find  no  evidence  whatever  in  support  of  the  state- 
ment made  by  Lelong  in  1888  that  "The  Australian  Navel 
was  introduced  by  Louis  Wolfskill  in  1874."  The  success- 
ful importation  of  the  true  Bahia  took  place  as  follows  : 

In  1870  William  Saunders,  then  in  charge  of  the  govern- 
ment propagating  grounds  at  Washington,  D,  C,  through 
the  assistance  of  a  lady  missionary  stationed  at  Bahia, 
Brazil,  had  twelve  trees  of  the  Bahia  Navel  orange  propa- 
gated and  sent  to  Washington  in  tubs.  All  twelve  of  these 
were  true  Bahia,  and  after  being  placed  in  the  greenhouse 
at  Washington  were  used  indiscriminately  as  a  source  of 
buds  from  which  were  propagated  a  number  of  trees  for 
distribution,  many  of  which  were  later  sent  to  Florida  and 
California.  All  twelve  of  these  original  trees  for  some 
reason  passed  out  of  existence.  The  first  lot  propagated 
was  distributed  to  California  and  Florida,  and  one  tree 
from  this  lot  was  planted  in  the  orange  house  at  Washing- 
ton, where  it  still  remains.  The  common  idea  that  this 
tree  in  Washington  is  the  original  tree  imported  is  wrong. 
It  was  propagated  from  one  of  the  original  twelve. 

The  active  settlement  of  Riverside,  California,  began 
about  1870,  and  was  extensively  advertised  in  the  East 
by  Judge  North,  the  founder  of  the  Colony.  Among  other 
settlers  attracted  were  Luther  C.  Tibbet  and  wife.  Early  in 
1873  Mrs.  Tibbet  (Fig.3)  was  in  Washington  just  previous 
to  starting  to  her  new  home  at  Riverside,  California.  While 
visiting  the  government  propagating  gardens,  Mr. 
Saunders  offered  to  give  her  some  trees  of  this  Bahia 
orange  and  she  gladly  accepted  two  trees,  which  she  carried 
to  California,  where  she  and  her  husband  planted  them 
beside  their  cottage  in  Riverside  on  land  which  they  had 


18 


Citrus  Fruits 


horaesteaded.  According  to  present  street  nomenclature 
the  spot  formerly  occupied  by  the  Tibbet  cottage  is  on 
Central  Avenue  near  Palm  Avenue.  The  fruit  from  these 
trees  first  attracted   attention  at  a  private  meeting  of 

fruit  growers  in  the 
winter  of  1877-88,  at 
which  time  the  Navel 
trees  sold  by  Thomas 
A.  Garey  had  been  in 
bearing  several  years. 
In  February,  1879, 
the  Southern  Cali- 
fornia Horticultural 
Society  (J.  De  Barth 
Shorb,  President,  and 
L.M.Holt,  Secretary) 
held  a  citrus  fair  at 
Riverside.  At  this 
fair  ISIr.  T.  D.  Cover 
exhibited  fruit  from 
the  Tibbet  trees  and 
was  awarded  first 
prize  over  other 
Navels  exhibited 
from  Orange  County, 
which  came  from 
trees  imported  from  Australia  by  Mr.  Garey.  The 
difl'erence  between  the  two  forms  was  recognized  by  ex- 
pert fruit  grow^ers;  the  Tibbet  oranges  being  called 
Washington  Navels  because  Mrs.  Tibbet,  probably  for- 
getting the  name  "Bahia,"  always  said  in  answer  to  in- 


FiG.  3. —  Mrs.  L.  C.  Tibbet,  who  first 
brought  the  true  Navel  orange  to  Cali- 
fornia. 


History  and  Development  of  the  Citrus  Industry     19 

quiries  that  the  trees  came  from  Washington.  All  other 
kinds  of  Navels  were  called  Australians  because  it  was 
supposed  that  they  all  came  from  Australia. 

A.  S.  White  of  Riverside  writing  in  the  Riverside  Press 
and  Ilorticulturist  under  date  of  June  26,  1880,  says,  — 
"  It  (Washington  Navel)  was  first  exhibited  at  the  River- 
side Citrus  Fair  last  year  (1879),  where  it  attracted  great 
attention,  its  appearance  being  so  unlike  the  other  Navels 
on  exhibition,  which  were  from  the  stock  imported  into 
California  from  Australia.  The  marked  points  of  differ- 
ence between  the  two  Navel  oranges  lie  in  their  external 
appearance.  Instead  of  being  like  the  Australian,  ribbed 
lengthwise,  it  is  smooth  and  more  globular.  The  skin 
is  of  a  finer  texture,  has  more  of  a  satin-like  appearance, 
and  shows  a  much  higher  color,  being  of  a  bronzy-gold 
tint." 

An  editorial  (presumably  by  L.  M.  Holt)  in  Riverside 
Press  and  Horticulturist,  in  1883,  says:  "We  have  but 
two  varieties  as  yet  of  the  so-called  Navel  orange.  The 
first  was  introduced  into  California  from  Australia. 
Both  varieties,  the  Washington  and  Australian  Navels, 
are  now  being  grown  quite  extensively  though  the  trees 
are  young  yet,  and  I  must  confess  it  is  at  times  a  puzzle 
to  distinguish  one  from  the  other,  under  test  conditions, 
and  I  believe  I  am  not  alone  in  this  position." 

After  studying  a  number  of  the  discussions  in  the  early 
literature,  the  writer  is  of  the  opinion  that  since  both  the 
true  and  false  form  of  Bahia  orange  existed  in  Australia, 
that  T.  A.  Garey's  original  importation  in  1870  was  mixed 
and  that  at  least  some  trees  sold  by  him  were  the  true 
Bahia.     How  else  can  we  account  for  the  fact  that  cer- 


20  Citrus  Fruits 

tain  reputable  and  apparently  experienced  men  insisted 
for  years  that  some  of  the  trees  sold  by  Garey  bore  fruit 
identical  with  that  of  the  Tibbet  trees  at  Riverside.  If 
this  is  true,  then  the  Tibbet  trees  were  not  the  first  genu- 
ine Bahia  Navels  to  reach  California.  It  is  a  fact  beyond 
dispute,  however,  that  the  Tibbet  trees  are  the  ones 
which  attracted  attention  and  were  undoubtedly  the 
direct  cause  of  the  great  boom  in  the  orange  growing 
business  which  began  in  the  early  80's. 

Giving  IVIrs.  Tibbet  two  trees,  Mr.  Saunders  sent  several 
trees  to  Florida  and  some  to  California.  Alexander  Craw, 
then  foreman  for  J.  M.  Asher,  a  nurseryman  of  San 
Diego,  is  said  to  have  received  two  of  these  trees.  It 
might  be  argued  that  jNIr.  Garey  secured  his  stock  of  Bahia 
from  Craw  or  even  from  Mr.  Saunders  at  Washington. 
This  is  barely  possible,  but  in  view  of  the  shortness  of 
time  thus  allowed  to  work  up  the  stock,  and  the  letters 
of  his  contemporaries  stating  the  contrary,  it  is  hardly 
probable. 

For  two  or  three  years  after  the  Tibbet  trees  began  to 
be  propagated  in  Riverside  this  orange  was  known  as  the 
Washington  Navel.  In  1883,  however,  a  determined 
effort  by  the  people  of  Riverside  was  made  to  change  the 
name  to  Riverside  Navel  in  order  (according  to  L.  M.  Holt 
in  Ontario  Fruit  Grower,  May  16,  1883)  that  Riverside, 
the  town  where  this  variety  happened  to  be  first  tested, 
might  get  the  benefit  of  the  advertising  which  would 
follow  the  use  of  this  name.  O.  H.  Conger  of  Pasadena 
and  others  vigorously  opposed  this  to  such  good  purpose 
that  the  name  Riverside  Navel  became  a  synonym. 

Luther  C.  Tibbet  is  known  to  have  been  rather  improvi- 


History  and  Development  of  the  Citrus  Industry    21 

dent.  He  never  owned  any  orange  trees  other  than  the 
two  his  wife  brought  from  Washington.  He  permitted 
his  homestead  to  pass  out  of  his  hands,  but  he  and  his  wife 


Fig.  4.  —  One  of  the  original  Washington  Na\il 
to  California. 


were  allowed  to  live  in  the  cottage  during  the  life  of  Mrs. 
Tibbet.  After  her  death  Tibbet  was  cared  for  at  the 
County  Hospital  until  he  died  July  1,  1902. 

In  1903  Louis  Jacobs  was  the  owner  of   the  Tibbet 


22 


Citrus  Fruits 


homestead.  He  gave  one  of  the  trees  to  Frank  A.  Miller, 
proprietor  of  the  Glenwood  Hotel,  who  had  it  removed 
to  its  present  location  in  front  of  the  hotel  May  7,  1903. 
President  Roosevelt,  a  guest  at  the  hotel  at  the  time, 
assisted  in  transplanting  this  tree,  for  the  care  of  which 
Mt.  Miller  is  now  responsible. 


Citrus  Acreage  ix  Counties  in  California  having  more 
THAN  10,000  Trees  in  1910 


Los  Angeles  .  . 
San  Bernardino 
Tulare  .  .  . 
Riverside  .  .  . 
Orange  .  .  . 
Ventura  .  .  . 
San  Diego  .  . 
Butte  .... 
Santa  Barbara  . 
Fresno  .... 
Kern  .... 
Sacramento  .  . 
San  Louis  Obispo 
Placer  .... 
Yolo  .... 
Glenn  .... 
Tehama  .  .  . 
Sonoma 

Colusa  .... 

Solano        .     .     . 

All  other  counties 

Total  for  state 


Number  of 
Trees 


3,283,500 

3,149,250 

2,985,000 

1,966,705 

1,149,605 

503,137 

395,974 

146,673 

144,270 

106,928 

78,500 

55,780 

39,000 

33,115 

18,575 

16,540 

13,565 

11,270 

11,000 

11,000 

56,797 


14,176,184 


43,780 

41,990 

39,800 

25,222 

15,328 

6,708 

5,279 

1,957 

1,924 

1,746 

1,033 

744 

520 

441 

247 

221 

180 

150 

146 

147 

754 


188,317 


History  and  Development  of  the  Citrus  Industry    23 

About  the  same  time  the  other  original  tree  was  given 
to  the  city  by  Mr.  Jacobs  and  it  was  transferred  to 
a  small  plot  of  ground  at  the  head  of  Magnolia  Avenue. 
J.  H.  Reed,  then  tree  warden  of  Riverside,  placed  a 
substantial  ornamental  iron  fence  around  it  which  affords 
protection  from  any  thoughtless  or  selfish  person.  The 
city  of  Riverside  is  responsible  for  the  care  of  this  tree. 
Both  the  original  trees  are  at  tliis  date  in  a  healthy  and 
flourishing  condition,  and  the  one  on  INIagnoha  Avenue 
especially  is  producing  fair  crops  (Fig.  4). 


CITRUS    GROWING    IN    ARIZONA    AND    SONORA 

The  citrus  industry  of  Arizona  is  hardly  more  than 
twenty-five  years  old,  although  occasional  orange  trees 
may  have  been  planted  at  a  very  much  earlier  date.  The 
first  plantings  of  any  importance  were  along  the  Arizona 
Canal  west  of  Scottsdale  in  the  Salt  River  Valley.  The 
Ingleside  orange  grove  on  the  foothills  of  Camel's  Back 
Mountain  was  the  largest  of  these  early  plantings,  and  it 
was  due  largely  to  its  success  that  the  acreage  was  in- 
creased in  this  locality. 

Another  important  prospective  citrus  area  is  on  Yuma 
Heights  near  Yuma,  where  an  old  orchard  ten  or  twelve 
acres  in  extent  has  served  for  many  years  to  indicate  the 
possibilities  of  this  area.  The  lack  of  water  develop- 
ment has  been  the  chief  hindrance  to  the  planting  of 
additional  acreage. 

While  California  received  its  first  orange  seed  from 
Sonora,  this  country  has  been  very  backward  in  its  citrus 
development,  chiefly  for    the    reason    that    it    has  been 


¥ 


24^^  i^^  Citrus  Fruits 


24^ 


Ajsol^ed   from  home    markets  and    liandieapped  by  the 
/^a^"  in  reaching  American  markets. 
^7     Xjeograi)hically  Sonora  })eh)ngs  to  the  Arizona  and  south- 
^  Astern  Cahfornia  areas  as  the  cHmate  and  soil  con{htions 
4X*are   very   similar.     The   chief   commercial   orchards   are 
situated  near  Hermosillo,  in  the  valley  of    the  Sonora 
River,  and  near  Guaymas.     The  production  of   fruit  at 
Guaymas  was  greatly  reduced  in  1905  by  a  serious  in- 
festation of  the  red  scale.     The  variety  chiefly  grown  at 
Hermosillo  is  the  sweet  seedling  orange.     The  production 
gradually  increased   and    in  1908    about  250  cars  were 
sent  in  bond  through  the  Ignited  States  to  Canada,  which 
they  enter  duty  free. 

The  oranges  produced  in  southern  Mexico,  especially 
in  the  states  of  Jalisco,  Morelos,  and  San  Luis  Potosi, 
where  the  climate  is  more  tropical,  differ  in  character 
from  those  grown  in  Sonora,  being  inferior  for  shipping. 
Much  of  southern  IVIexico  is  infested  with  the  Morelos 
orange  maggot,  Trypeta  ludens,  and  this  interferes  with 
the  marketing  of  the  fruit. 


CHAPTER  II 

CITRUS    GEOGRAPHY   AND    CLIMATOLOGY   OF 
CALIFORNIA 

Citrus  fruits  originated  in  India  and  the  Malay  Archi- 
pelago and  are  generally  regarded  as  tropical  fruits,  yet 
it  is  a  curious  fact  that  the  greatest  commercial  success 
with  them  has  been  obtained  in  semitropical  countries. 
This  statement  applies  especially  to  oranges  and  to  a  less 
extent  to  limes  and  pomelos.  The  bulk  of  the  oranges 
which  supply  the  markets  of  the  world  are  produced  in 
countries  which  experience  a  certain  degree  of  frost,  such 
as  California,  Spain,  Florida,  Palestine,  Austraha,  Japan, 
and  Italy.  Oranges  grown  in  moist  tropical  coun- 
tries are  lacking  in  tartness,  color,  shipping  and  keep- 
ing quahties.  All  of  these  qualities,  so  desirable  in  a 
marketable  orange,  become  more  marked  as  we  approach 
the  line  where  frequency  of  frosts  makes  the  culture  of 
the  trees  unprofitable. 

The  citrus  producing  lands  of  California  are  scattered 
from  San  Diego  to  Shasta  County,  a  north  and  south  dis- 
tance of  four  hundred  and  fifty  miles.  It  is  a  peculiar 
fact  that  there  are  orange  orchards  in  California  in  the 
same  latitude  with  New  York  City  and  Lincoln,  Nebraska. 
This  is  made  possible  by  the  peculiar  topography  of  the 
25 


26  Citni.'i  Fruits 

state,  whereby  the  mountain  ranges  are  so  situated  that 
the  cold  winds  of  the  north  are  shut  out  from  interior 
valleys,  and  the  full  effects  of  the  abundant  winter  sun- 
shine allowed  to  accumulate.  Along  the  southern  coast 
also  the  mild  moisture  laden  breezes  from  the  Pacific 
modify  the  climate  of  the  country  between  the  mountains 
and  the  sea  without  interference  from  northern  blasts, 
which  are  diverted  eastward  by  the  mountain  barrier  in 
northern  (\difornia.  Yrom  the  point  of  view  of  the 
fruit  grower,  longitude  is  more  important  than  latitude. 
Fig.  5  shows  the  distribution  of  the  citrus  areas  of 
California. 

CLASSIFICATION    OF    CITRUS    AREAS 

The  areas  where  climatic  conditions  permit  the  growth 
of  citrus  trees  may  be  roughly  grouped  into  three  divi- 
sions and  designated  as  the  Southern  Coast,  Interior 
Valleys,  and  Northern  Coast  Divisions,  in  the  order  of 
their  importance  as  citrus  producing  areas. 

The  Interior  Valleys  Division  includes  the  Sacramento, 
San  Joaquin,  Upper  Santa  Ana,  Coachella,  Imperial,  and 
Colorado  Valleys  and  embraces  all  the  country  not  imme- 
diately adjacent  to  or  within  the  influence  of  the  ocean. 
The  Southern  Coast  Division  includes  all  the  citrus 
country  between  the  mountains  and  the  sea  as  far  north 
as  Santa  Barbara.  The  Northern  Coast  Division  includes 
all  the  country  within  the  influence  of  the  sea  from  Santa 
Maria  as  far  north  as  northern  Sonoma  County.  The 
amount  of  rainfall  varies  much  in  different  parts  of  the 
state,  but  the  rainy  season  is  fairly  uniform,  being  from 
November  to  March  inclusive  throughout  each  of  these 


^7/  >^'^f^-  "^^^ 


S     K,  I    V    0    U 


POSSIBLE     AREA 
PLANTED     AREA 


Fig.  5.  —  Cilifoniia  citrus  areas. 


(27) 


28 


Citrus  Fruits 


areas.  Rainfall  in  the  summer  is  very  rare  and  thunder 
and  lightning  exceedingly  rare  especially  near  the  coast. 
As  the  citrus  industries  of  these  three  divisions  differ 
in  many  particulars,  we  will  discuss  each  division  sepa- 
rately. 

The  Southern  Coast  Division 

The  climate  of  this  section  is  characterized  by  an  equa- 
ble temperature  with  cool  summers  and  warm  winters. 


Fig.  6.  —  Four-year-old  Valencia  orange  grove  in  Los  Angeles  County. 


The  rainfall  is  about  18  inches  in  the  northern  but  de- 
creases in  the  southern  part.  The  air  is  quite  moist  as 
compared  with  the  interior,  and  there  are  frequent  fogs 
and  overcast  skies.  The  prevailing  breezes  are  from  the 
Pacific  Ocean,  which  has  a  surface  temperature  not  far 
from  60°  F.  at  all  seasons  of  the  year.  The  extent  of  the 
ocean  influence  depends  upon  local  topography,  being 
narrow  in  Santa  Barbara  County  and  widening  out 
toward  the  south  and  including  the  San  Gabriel  Valley 
which  contains  the  most  highly  developed  and  largest, 


Citrus  Geography  and  Climatology  of  California     29 

contiguous  citrus  area  in  the  state.  Fig.  6  shows  a 
representative  orange  plantation  in  southern  California. 

In  general,  the  soils  of  this  region  are  deep  and  very 
fertile,  being  heavier  near  the  coast  and  lighter  in  charac- 
ter toward  the  interior.  The  two  prevailing  soil  types 
are  the  Placentia  series,  resulting  from  the  weathering 
of  reddish  granite,  which  outcrops  at  many  places,  and  the 
Maricopa  series,  which  are  alluvial  in  nature,  being  an 
ancient  flood  plain.  These  latter  soils  are  darker  in  color 
and  often  contain  smooth  cobbles  and  bowdders  invariable 
amounts.  Less  important  soil  types  are  the  black  adobe 
sometimes  found  on  the  foothills  and  the  light  sandy 
soils  of  the  river  bottoms. 

While  the  prevailing  breezes  are  westerly,  this  section  of 
country  is  occasionally  visited  by  characteristic  hot 
northers  which  blow  with  force  for  several  days  at  a  time 
from  the  northeast.  At  such  times  the  air  becomes 
excessively  dry  and  high  temperatures  prevail.  Such 
desiccating  winds  are  sometimes  quite  injurious  to  vege- 
tation and  cause  a  severe  loss  of  water  from  plants  and  soil. 
It  is  fortunate  that  such  winds  are  not  of  more  frequent 
occurrence. 

The  southern  coast  is  especially  adapted  to  the  growing 
of  lemons,  which  here  produce  a  larger  proportion  of  high- 
priced  summer  fruit.  Stored  lemons  also  keep  better  and 
expensive  storehouses  are  not  needed  as  is  the  case  in 
interior  valleys.  The  cool  summers  also  make  it  possible 
to  hold  Valencia  oranges  on  the  trees  until  the  follow- 
ing October  and  November,  when  very  high  prices  are 
often  realized.  This  section  of  country  is  also  well  suited 
to  the  production  of  nursery  stock,  which  is  grown  in  very 


30  Citrus  Fruits 

large  quantities,  the  San  Gabriel  Valley  being  the  center 
of  this  industry. 

The  Washington  Navel  orange  here  produces  very 
heavy  crops,  but  the  fruit  ripens  later  and  is  somewhat 
inferior  to  that  produced  in  interior  valleys  both  as  re- 
gards color,  texture,  flavor,  and  shipping  qualities. 

The  Interior  Valley  Division 

The  climate  of  all  the  interior  valleys  is  characterized 
by  conditions  more  or  less  extreme.  The  air  is  nearly 
always  dry  and  this  permits  rapid  radiation,  causing  a 
wide  range  in  temperature  each  day.  Rainfall  is  fairly 
abundant  in  winter  in  the  northern  valleys  and  less  so 
tovv'ard  the  south.  The  air  is  free  from  fogs  and  dew  in 
summer  and  constant  sunshine  is  the  rule.  The  days 
are  often  very  hot,  while  the  nights  are  always  cool. 

The  floors  of  the  valleys  are,  as  a  rule,  frosty  in  winter 
and  on  this  account  the  principal  citrus  areas  are  found 
along  the  foothiUs,  above  the  frost  line,  and  where  irriga- 
tion water  is  available.  Such  areas  are  usually  at  an  eleva- 
tion of  from  500  to  1500  feet  above  the  sea,  and  from  100 
to  500  feet  above  the  floor  or  "draw"  of  the  valley.  In 
such  locations  a  few  feet  in  the  perpendicular  is  of  far 
greater  importance  to  the  citrus  grower  than  many  miles 
in  the  horizontal.  That  is  to  say,  whether  the  orchard 
is  planted  in  a  "draw"  or  on  a  bluff  above  it,  yet  on  the 
same  ranch,  may  mean  more  for  the  success  or  failure  of 
the  grove  than  whether  the  trees  are  planted  near  Holt- 
ville  or  at  Oroville  five  hundred  and  fifty  miles  distant. 
Cold  air  is  heavy  and  on  quiet  nights  flows  down  and  col- 


Citrus  Geography  and  Climatology  of  California     31 

lects  in  the  lowlands,  leaving  the  foothills  above  the  frost 
line. 

In  the  central  valleys  oranges  ripen  very  early  and 
as  some  of  these  are  far  to  the  north  of  the  Coast  Coun- 
try, the  unusual  procedure  of  shipping  earliest  ripening 
fruits  southward  to  market  is  accounted  for. 

The  largest  producing  district  in  this  division  lies  on  the 
eastern  foothills  of  Tulare  County,  including  Woodlake  and 
Porterville,  at  an  elevation  of  four  or  five  hundred  feet 
above  sea-level.  One  of  the  typical  soils  of  this  district 
is  known  as  the  Porterville  clay  loam  adobe,  which  is  a 
residual  soil  characteristic  of  the  higher  foothill  slopes. 
Lower  down  the  valley  slopes  are  found  soils  of  the  San 
Joaquin  series,  which  are  sometimes  characterized  by 
"hog-wallows"  and  a  certain  amount  of  hardpan.  The 
valley  floor  is  composed  mostly  of  alluvial  soils  of  the 
Hanford  series. 

In  the  northern  Sacramento  Valley  the  soils  are  very 
variable,  but  are  mostly  of  a  reddish  color.  They  are  in 
large  part  sedimentary  soils  of  the  San  Joaquin,  Stockton, 
Alamo,  and  other  series.  While  there  are  many  exceptions, 
it  is  true  that  these  soils,  especially  on  the  east  side  of 
the  valley,  are  quite  generally  underlaid  by  a  stratum  of 
dense,  impervious  hardpan  which  occurs  at  variable 
depths.  Where  hardpan  is  near  the  surface,  the  land  is 
not  suited  to  citrus  fruits  unless  it  be  dynamited  and  the 
hardpan  thoroughly  broken  up. 

The  Northern  Coast  Division 

In  outline  this  division  is  very  irregular,  consisting  in 
places  of  a  narrow  strip  between  the  mountains  and  the 


32  Citrus'  Fruits 

sea  and  extending  occasionally  into  valleys  where  the  hills 
are  low  and  do  not  entirely  shut  ofl"  the  cool,  moist  sea- 
breezes.  East  of  the  bay  region  the  coast  influences 
extend  far  inland,  following  the  Sacramento  River  and 
tempering  the  climatic  conditions  at  the  junction  of  the 
San  Joaquin  and  Sacramento  Valleys  to  such  an  extent 
that  the  region  between  the  cities  of  Stockton  and  Sacra- 
mento is  really  intermediate  in  climatic  characteristics. 
The  climate  of  the  Northern  Coast  forms  a  strong  con- 
trast with  that  of  the  interior  valleys.  It  is  comparatively 
free  from  extremes  of  temperature,  being  warm  in  winter 
and  cool  in  summer.  The  w^inter  rainfall  is  usually  heavy 
and  there  is  much  fog  in  summer.  Here  green,  grass- 
covered  hills  are  the  rule  instead  of  the  bare  rocky  buttes 
of  the  interior. 

There  are  no  large  commercial  citrus  areas  within  this 
district,  yet  oranges  and  lemons  are  grown  in  yards  and 
gardens  and  the  product  is  used  for  local  consumption 
throughout  the  district.  The  total  amount  of  summer 
heat  is  small,  and  oranges  do  not  yield  well  as  a  rule  nor 
is  the  fruit  high  in  sugar  content.  The  color  also  is  poor 
on  account  of  the  lack  of  abundant  sunshine,  and  the  trees 
are  subject  to  the  ravages  of  many  insect  pests  and  fungous 
diseases  which  are  not  able  to  survive  the  hot  summers 
of  the  interior  valleys.  The  trunks  and  branches  of  trees 
on  the  coast  are  apt  to  become  covered  with  a  growth 
of  lichens  and  alga?  which  should  be  removed  with  alkali 
sprays. 

The  soils  of  the  coast  country  are  chiefly  deep  rich 
residual  soils  formed  by  the  gradual  weathering  and 
breaking  down  of  the  local  rock  masses. 


Citriis  Geography  and  Clinuitologij  of  California     33 

THE    FROST    HAZARD 

It  has  been  asserted  that  certain  districts  in  Cahfornia 
are  free  from  frost.  This  is  hardly  true,  for  a  certain 
frost  hazard  exists  in  all  districts  both  north  and  south. 
Almost  all  districts  on  the  other  hand  embrace  certain 
areas  which  are  comparatively  frost  free.  One  thing 
which  usually  impresses  the  stranger  from  the  East  most 
forcibly  is  the  sharpness  with  which  the  frost  lines  are 
drawn.  There  are  many  ranches  of  a  hundred  acres  or 
less  which  are  divided  by  these  frost  lines  into  citrus 
lands,  walnut  lands,  and  alfalfa  lands.  It  is  often  very 
difficult  to  accurately  judge  the  frost  hazard  on  any  given 
piece  of  land  unless  there  be  an  old  orchard  alongside 
upon  the  history  of  which,  together  with  the  local  topog- 
raphy, an  estimate  may  be  based.  Failures  due  directly 
to  faulty  judgment  in  regard  to  the  frost  hazard  are  almost 
without  number. 

In  recent  years  the  science  of  orchard  heating  as  de- 
scribed in  Chapter  XIV  has  enabled  growers  to  insure 
their  crops  against  occasional  frosts,  but  where  orchards 
must  be  heated  many  nights  each  winter  the  expense  is 
quite  likely  to  interfere  with  the  profits. 

We  may  conclude  then  that  throughout  the  citrus  divi- 
sions of  the  Southwest  there  are  specially  favored  dis- 
tricts where  citrus  fruits  grow  to  perfection  and  are  seldom 
injured  by  cold.  Within  each  of  these  districts,  however, 
there  are  many  localities  of  irregular  outline  and  extent 
which  on  account  of  local  topography  are  quite  out  of  the 
question  as  citrus  lands.  On  this  point  Lelong  ^  writes  as 
follows : 

1  "Culture  of  the  Citrus  in  California,"  1902. 

D 


34  Citrus  Fruits 

"Wherever  cold  currents  of  air  from  high  altitudes 
flow  to  the  valley  without  interruption,  it  will  not  be  safe 
to  attemi)t  citrus  culture  at  any  elevation  within  the  sweep 
of  these  currents.  On  the  other  hand,  wherever  the 
descending  currents  are  cut  off  or  turned  aside  by  spurs 
of  the  mountains,  leaving  the  warm  atmosphere  of  the 
days  undisturbed  during  the  nights,  there  orange  and 
lemon  culture  may  be  engaged  in  with  little  danger  from 
frost.  In  other  words,  the  eddies  of  air  currents  must  be 
selected  and  the  main  flow  of  these  currents  must  be 
avoided. 

"  Everybody  who  has  traveled  along  the  Sierra  foothills, 
parallel  with  the  valleys,  particularly  in  the  winter  season 
and  at  night,  will  recall  his  surprise  at  the  sudden  changes 
of  the  temperature  of  the  atmosphere  within  short  dis- 
tances. He  may  also  remember  to  have  noticed  tender 
plants  and  shrubs  seared  and  frost-bitten,  while  just  over 
a  ridge  or  cone  the  same  plants  and  shrubs  were  in  full 
leaf  and  growing  luxuriantly.  Want  of  attention  to  these 
facts  has  caused  many  a  disastrous  failure  in  the  culti- 
vation of  citrus  fruits  in  California." 


ATMOSPHERIC    HUMIDITY 

In  the  interior  valleys  which  are  fanned  by  dry  desert 
breezes,  the  amount  of  atmospheric  moisture  is  very  low, 
and  this  together  with  the  great  heat  tends  to  produce 
oranges  of  high  sugar  content  and  with  very  desirable 
deep  red  color.  Dry  air  also  discourages  the  growth 
of  certain  diseases  affecting  the  tree,  as  well  as  certain 
scale  insects,  lichens,  and  algae  which  cannot  endure  the 


Citrus  Geography  and  Climatology  of  California     35 

desert  conditions.  On  the  other  hand,  lemon  trees  under 
such  climatic  conditions  tend  to  bear  only  one  crop  a  year, 
and  the  proper  curing  and  keeping  of  lemons  is  made 
more  difficult.  The  moist  and  foggy  coast  country  with 
its  cool  sea  breezes  brings  about  a  somewhat  different 
phase  of  the  industry.     Here  lemons  tend  to  bear  a  con- 


^^^^^^H|^H 

^pp-.r 

H^^UHBBBMMim^P^  ^^ 

Fig.  7. 


•Typical  scene  in  Los  Angeles  C'ouiity. 
robusta  on  right. 


Windbreak  of  (ii 


tinuous  crop  the  year  round,  and  the  fruit  may  be  easily 
stored  in  open  sheds  and  kept  in  good  condition  for  six 
or  eight  months.  Oranges  near  the  coast  are  six  or  eight 
weeks  later  in  ripening  than  those  of  the  interior,  and  the 
trees  are  subject  to  a  larger  number  of  the  insect  pests 
and  diseases  to  which  the  citrus  tree  is  heir. 


36 


Citni.i  Fruits 


WINDS 


Stn)iig   winds  are   a   serious   hindrance   to   the  citrus 
grower.     The  young  foHage  is  badly  torn  or  may  even  be 


Nfc^u, 


Fic;.  S.  —  Pinus  radiata,  ii  iiiitivf  |)iiu'  used  ;i.s  ;i  winclhiciik. 

blown  from  the  trees ;  the  fruit  is  bruised,  scarred,  and 
covered  with  unsightly  callous  marks ;  the  trees  are  pre- 
vented from  forming  symmetrical  heads ;  and  in  some 
cases  the  soil  itself  is  either  blown  away  from    the  roots 


Citrus  Geography  and  Cliniatologt/  of  California      37 

or  banked  too  deep  around  the  trunks  of  the  trees.  In 
some  extreme  cases,  the  traveling  sand  wears  away  the 
bark  of  young  trees  near  the  ground.  As  a  rule,  windy 
locations  should  be  avoided  in  selecting  a  site  for  a  citrus 


Fi(i.  9.  —  Orange   tree   denuded   of  foliage  on  windward   -sido   by   three 
days  of  desert  wind. 


orchard.  In  some  cases,  however,  where  all  the  other 
conditions  are  right,  the  force  of  the  wind  may  be  broken 
by  growing  windbreaks  of  cypress,  eucalyptus,  or  cedar. 
Care  should  be  exercised  that  the  windbreak  is  not 
allowed  to  grow  too  thick  and  become  a  "wind-stop," 


38  Citrii.'i  Fruits 

as  this  may  interfere  with  atmospheric  drainage  and  make 
a  frost  pocket  of  the  grove.  A  Hve  windbreak  is  ob- 
jectionable on  the  ground  that  the  roots  approj)riate  the 
plant  food  and  water  from  one  or  two  rows  on  either  side 
and  seriously  interfere  with  the  fruiting  of  the  orchard 
trees.  This  trouble  may  be  obviated  to  some  extent  by 
digging  a  trench  ten  feet  from  the  windbreak  and  three 
feet  deep  every  second  year  and  cutting  all  the  feeding 
roots.  Care  should  be  used  in  selecting  varieties  of  trees 
for  windbreaks  that  they  may  not  be  host  plants  for 
insects  which  affect  citrus  trees.  The  pepper  tree, 
Schijius  molle,  for  example,  makes  an  excellent  wind- 
break and  is  largely  used  in  interior  valleys  where  the 
black  scale  is  of  less  importance.  Near  the  coast  such 
trees  may  have  to  be  fumigated  occasionally  at  great 
expense.  Figs.  7  and  8  show  windbreaks  of  the  silk  oak 
(GreviUea  robusta)  and  Monterey  pine  {Pinus  radiata), 
which  are  much  used  in  parts  of  California.  Fig.  9  il- 
lustrates the  damaging  effect  of  the  wind. 

SUNLIGHT 

While  a  certain  amount  of  sunlight  is  absolutely  neces- 
sary for  plant  growth,  there  are  places  in  California  where 
citrus  plants  are  over-illuminated.  Sunburn  of  the 
fruit  and  tree  trunks  and  even  of  the  leaves  often  occurs 
in  the  dry  interior  valleys,  where  the  lack  of  moisture  in 
the  air  permits  the  actinic  rays  of  the  sun  to  strike  the 
trees  with  full  force.  In  such  situations,  the  fruit  borne 
on  the  outside  of  the  trees  and  fully  exposed  to  the  light 
is  inferior  and  often  ruined,  while  the  fruit  which  is 


Citrus  (ieography  and  Climatology  of  California     39 

screened  by  foliage  may  be  of  the  very  finest  quality.  It 
is  the  custom  among  nurserymen  to  shield  citrus  seedlings 
from  the  light  by  growing  them,  for  the  first  six  or  eight 
months,  under  lath  screens  so  arranged  as  to  reduce  the 
total  light  about  75  per  cent.  Running  the  lath  north 
and  south  will  provide  alternating  light  and  shadow 
for  any  given  seedhng  as  the  sun  moves  from  east  to  west. 


CHAPTER  III 

CITRUS    BOTANY,     GROSS    STRUCTURE,    AND 
HABITS  OF  GROWTH 

Citrus  fruits  differ  from  olives,  figs,  dates,  and  pome- 
granates in  being  of  comparatively  modern  origin.  They 
emerged  from  the  wild  state  in  the  Malay  Archipelago 
and  southern  Asia.  Certainly  citrus  fruits  were  not 
known  by  civilized  peoples  until  comparatively  recent 
times.  The  ancient  Egyptians  did  not  know  the  citrus 
fruits.  The  Romans  did  not  know  the  orange  or  any 
other  edible  form  except  perhaps  the  citron  at  the  be- 
ginning of  the  Christian  Era.^  While  the  Old  Testament 
makes  frequent  mention  of  olives,  pomegranates,  figs,  and 
other  fruits,  no  mention  is  made  of  any  citrus  fruit  unless 
we  except  the  word  "hadar"  translated  "goodly  trees" 
(Leviticus  23  :  40)  as  referring  to  the  citron.  Risso,^  one 
of  the  most  able  of  the  early  writers  on  citrus,  compared 
the  ancient  texts  and  claims  that  this  word  merely  refers 
to  any  beautiful  or  fine  tree.  It  is  likely  that  the 
Hebrews  became  acquainted  with  this  fruit  at  the  time 
of  the  Babylonish  captivity.  Be  this  as  it  may,  the 
Jews  believe  this  word  refers  to  the  citron,  or  etrog  as 

1  De  Candolle,  "Origin  of  Cultivated  Plants,"  p.  181. 

^  Risso  and  Poiteau,  "Histoire  Naturelle  des  Grangers." 

40 


Citrus  Botany,  Gross  Structure,  and  Habits  of  (trowth     41 

it  is  called  by  them,  and  to  this  day  they  present  them- 
selves at  the  synagogue  on  the  day  of  the  Feast  of 
Tabernacles,  as  commanded  in  Leviticus,  with  a  citron 
in  their  hands  together  with  an  unopened  date  palm 
leaf,  a  three-parted  branch  of  myrtle,  and  a  willow  twig. 

The  citron,  known  by  the  Romans  as  Malum  persicum, 
the  apple  of  the  Persians,  was  transplanted  to  Italy  about 
the  third  or  fourth  century. 

The  lemon  was  not  brought  to  southern  Europe  until 
after  the  tenth  century,  and  the  earliest  Italian  reference 
to  it  is  dated  1250  a.d. 

The  bitter  or  sour  orange  was  unknown  to  the  early 
Greeks  and  Romans.  It  probably  originated  ,in  eastern 
India  and  spread  westward  slowdy.  When  it  reached 
Mesopotamia  it  received  the  Sanskrit  name  nagarunga, 
which  was  changed  to  verunga  and  arangi.  In  medieval 
Latin  it  became  arancium and  RnixWy  aurantium,  the  present 
Latin  name  from  which  our  English  word  orange  is  de- 
rived. The  Crusaders  saw  the  bitter  orange  in  Palestine. 
It  was  taken  by  the  Arabs  to  Sicily  in  1002,  spread  from 
there  to  Spain,  from  whence  it  was  taken  to  Florida  soon 
after  the  settlement  of  that  Colony.  In  Florida  the  bitter 
or  sour  orange  ran  wild,  and  dense  thickets  exist  there 
to-day  which  yield  the  greater  part  of  the  sour  orange 
seeds  planted  by  California  nurserymen. 

It  is  most  remarkable  that  so  good  a  fruit  as  the  sweet 
orange  should  not  have  been  known  to  ancient  writers, 
yet  they  make  no  mention  of  it.  In  fact  the  sweet  orange 
was  not  introduced  into  Europe  until  the  beginning  of 
the  fifteenth  century,  when  the  Portuguese  brought  im- 
proved forms  of  it  from  south  China.     A  number  of  writers 


42  Citrus  Fruits 

speak  of  the  sweet  orange  as  cultivated  in  Spain  in  the 
sixteenth  century.  At  a  very  early  date  the  Portuguese 
carried  the  orange  to  Brazil,  where  it  ran  wild  as  it  did  in 
Florida.  From  Brazil  the  orange  spread  southward  into 
Paraguay,  part  of  Uruguay,  and  northern  Argentina 
where  large  areas  are  now  covered  with  a  natural  growth 
of  wild  sweet  orange  trees. 

CLASSIFICATION 

The  genus  Citrus  belongs  to  the  family  Rutaceop  and  rep- 
resents the  highest  development  within  the  family.  There 
are  no  species  of  citrus  native  to  either  North  or  South 
America.  A  relative  is  the  prickly  ash  or  "  toothache 
tree,"  Xanthoxylum  americanum,  of  the  southeastern 
United  States. 

No  two  systematic  botanists  appear  to  be  agreed  as  to 
the  proper  classification  of  the  many  different  species. 
This  is  probably  due  to  the  fact  that  several  of  the  species 
hybridize  readily  and  it  is  very  difficult  to  determine 
which  of  the  forms  are  of  hybrid  origin.  The  writer  makes 
no  pretense  to  having  solved  this  perplexing  problem  by 
independent  botanical  research.  He  has  simply  studied 
the  different  schemes  proposed  and  from  them  arranged  a 
practicable,  working  classification  for  the  use  of  students, 
fruit-growers,  and  others  who  desire  a  simple  bird's-eye 
view  of  the  ten  species  in  which  they  are  chiefly  interested. 
Persons  particularly  interested  in  citrus  botany  are 
referred  to  Hume,  "  Citrus  Fruits  and  their  Culture  " ; 
to  Bonavia,  "  Oranges  and  Lemons  of  India  " ;  and  to 
Swingle,  "Citrus"  in  "Bailey's  Standard  Cyclopedia  of 
American  Horticulture." 


Citrus  Botany,  Gross  Structure,  and  Habits  of  Growth     43 


Citrus 


(rifoliata 

bergamia, 

sinensis, 

Aurantium, 

nohilis 


decumana, 
japonica, 

Medica, 
Limonia, 


the    deciduous    orange    {Poncirus    tri- 
foliata). 

Bergamot  orange. 

common  sweet  orange. 

sour  stock,  Seville,  or  bitter  orange. 
[  the  King  orange. 

I  Far.   deliciosa  —  the  Mandarin  or  kid- 
I       glove  orange.     Tangerine. 
[  Var.  unshiu  —  the  Satsuma  orange. 

the  pomelo  (grapefruit),  shaddock. 

kumquats. 

citron  of  commerce. 

sour  lemon,  sweet  lemon. 


aurantifolia,       sour  lime,  sweet  lime. 


All  of  these  ten  species  are  now  grown,  to  some  extent 
at  least,  in  California,  although  some  of  course  are  very 
much  more  important  than  others. 

Citrus  trifoliata.  —  This  is  the  only  deciduous  orange. 
The  fruit  is  not  edible.  It  is  highly  ornamental  and  very 
hardy  to  cold,  being  used  in  yard  and  garden  plantings  and 
for  hedges  as  far  north  as  Washington,  D.  C.  It  is  used  to  a 
certain  extent  in  Florida  and  more  generally  in  Texas  as  a 
stock  upon  which  to  bud  edible  oranges.  Its  use  as  a  stock 
in  California  was  never  widespread,  and  is  now  almost  obso- 
lete. Citrus  trifoliata  has  recently  been  used  to  a  considerable 
extent  in  breeding  work,  the  object  being  to  combine  the  cold 
resisting  qualities  of  the  trifoliata  with  the  good  qualities 
of  the  more  tender  species  which  bear  edible  fruit.  It  is 
native  to  Japan  and  China  and  was  introduced  into  Europe 
more  than  one  hundred  years  ago.  This  species  is  now  by 
some  put  in  the  genus  Poncirus,  becoming  P.  trifoliata. 

Citrus  bergamia.  —  The  Bergamot  orange  from  which  the 
oil  of  bergamot  is  made  is  grown  commercially  in  Europe. 
In  California  it  is  grown  only  as  an  occasional  specimen  or 
as  a  hedge  plant  in  gardens. 


44  Citrus  Fruits 

Citrus  sinensis.  —  The  ordinary  sweet  oranges  including 
such  varieties  as  Washington  Navel,  Valencia,  Mediterra- 
nean Sweet,  Ruby  Blood,  and  a  long  list  of  others. 

Citrus  Aurautium.  —  This  is  the  sour  or  bitter  bigarade 
orange,  the  fresh  fruit  of  which  is  hardly  edilile,  but  which  is 
coming  to  be  used  more  and  more  in  the  flavoring  of  marma- 
lades and  various  other  by-products.  Seedlings  of  this  orange 
have  almost  entirely  superseded  others  as  a  stock  upon  which 
to  grow  all  kinds  of  citrus  fruits  in  California.  The  reason 
for  this  is  its  superior  resistance  to  gum-disease  and  foot-rot. 
The  seed  from  which  this  "sour  stock"  is  grown  comes 
chiefly  from  the  wild  thickets  in  Florida.  In  Europe  this 
form  is  often  called  the  Se\'ille  orange. 

Citrus  nohilis.  —  The  description  of  this  species  was  l)ased 
on  a  form  very  like  the  King  orange.  It  includes  the  var. 
ddiciosa,  the  ordinary  Mandarin  oranges  such  as  the  Tan- 
gerine and  the  var.  unshiu,  which  is  the  Satsuma  orange. 

Citrus  dccumana.  —  Here  are  included  the  pomelos,  often 
incorrectly  called  "grapefruit,"^  and  the  shaddock.  They 
are  vigorous  grownng  trees  with  very  dark  green  leaves,  very 
prolific  in  bearing.  The  pomelo  is  growing  rapidly  in  public 
esteem,  but  the  shaddock  is  inedible.  The  shaddock  is  the 
largest  of  all  the  citrus  fruits,  but  has  an  extremely  thick 
skin  and  bitter  juice.  It  is  the  only  citrus  which  has  hairs  or 
pubescence  on  the  young  twigs  and  imder  sides  of  the  leaves, 
and  is  grown  only  for  ornament  or  curiosity. 

Citrus  japonica  (recently  referred  to  the  genus  Fortunella). 
—  The  Kumquats,  Kin-Kans,  or  golden  oranges,  small 
bushy  plants  from  Cochin-China.  The  fruits  are  small,  with 
mostly  acid  pulp  and  sweet  aromatic  rinds,  for  preserving 
and  for  decorations. 

^  The  term  "grapefruit"  has,  chiefly  through  the  influence  of 
"  the  trade,"  become  adopted  by  common  usage,  and  it  is  hardly 
worth  while  now  to  insist  on  th(>  xiso  of  the  more  correct  term. 


Citrm  Botany,  Gross  Structure,  and  Habits  of  Growth     45 

Citrus  Mcdica.  —  The  citron  from  wliich  the  candied 
citron  sold  by  grocers  is  made.  The  form  known  in  CaH- 
fornia  as  the  Chinese  lemon  and  much  used  in  the  early 
days  as  a  stock  is  thought  to  belong  here. 

Citrus  Limonin.  —  The  lemons  including  both  the  sour 
lemons  and  the  sweet  lemons. 

Citrus  aurantifolia.  —  The  limes  including  both  the  sour 
Mexican  and  Rangpur  limes  and  the  sweet  limes  which 
latter  are  considered  to  be  of  hybrid  origin. 

THE    CITRUS    PLANT 

The  Root 

Citrus  trees  differ  from  many  plants  in  having  no  root- 
hairs  whatever  upon  the  fibrous,  feeding  roots.  The 
feeding  roots  are  comparatively  large,  very  abundant,  and 
grow  very  rapidly.  Those  sheared  off  each  year  by  the 
plow  in  turning  under  a  cover  crop  are  quickly  replaced. 
In  shallow  soils,  however,  where  most  of  the  fibrous  roots 
are  near  the  surface,  it  is  unwise  to  be  too  reckless  with  the 
large  turning  plow.  Under  arid  conditions  the  feeding 
roots  are  not  confined  to  the  surface  layer  of  soil,  but 
where  there  is  no  layer  of  hardpan  to  interfere  they  dis- 
tribute themselves  throughout  the  soil  usually  between  the 
eighth  and  thirty-sixth  inch  levels.  In  very  deep,  well 
aerated  soils  they  may  forage  much  deeper. 

The  large  main  roots  serve  in  a  double  capacity; 
as  braces  to  hold  the  tree  upright  against  the  wind, 
and  as  conveyors  of  water  and  food  between  the  fibrous 
feeders  and  the  trunk.  Large  perpendicular  roots  known 
as  tap-roots  are  not  essential  to  the  health  or  w^ell-being  of 
the  trees  and  are  invariably  cut  when  the  young  nursery 


46  Citrus  Fruits 

trees  are  dug  for  transplanting.  Subsequently  the  sweet 
orange  root  will  devote  itself  mainly  to  sending  out  laterals, 
while  the  sour  orange  will  usually  send  down  two  or  three 
strong  tap-roots  in  the  place  of  the  one  w^hich  w^as  cut. 
The  pomelo  shows  much  variation  in  regard  to  the 
formation  of  tap-roots. 

Wood  Structure  and  Grouih 

Citrus  wood  is  very  closely  knit  in  structure,  being 
hard,  strong,  and  tough.  It  is  light  in  color,  with  very  fine 
grain  and  with  no  apparent  heart  wood ;  that  is,  there  is 
no  difference  in  color  between  heart  wood  and  sap  wood. 
The  rings  observable  in  a  cross  section  are  close  together 
and  are  of  no  value  in  determining  the  age  of  the  citrus 
tree,  as  they  are  in  the  case  of  pine  or  oak  trees.  This  is 
on  account  of  the  fact  that  the  citrus  tree  forms  several 
rings  each  year  according  to  the  number  of  vegetative 
growths.  The  citrus  tree  does  not  grow  at  a  uniform  rate 
during  the  season,  but  makes  three  or  more  growths  of  new 
twigs  and  leaves  each  year,  with  corresponding  rest  periods. 
The  heaviest  growth  is  in  the  spring  just  before  blooming, 
the  flowers  being  borne  on  the  new  shoots.  Another 
smaller  and  more  irregular  growth  is  made  in  mid-summer, 
and  a  third  in  the  late  fall.  The  number  of  growths  made 
and  the  times  they  occur  vary  with  the  local  weather  con- 
ditions and  the  method  of  irrigation. 

The  main  framework  branches  of  old  lemon  trees  often 
present  a  curious  flattened  shape  next  the  trunk.  The 
greatest  diameter  is  perpendicular,  but  the  width  of  the 
rings  is  much  thicker  on  the  lower  than  the  upper  side,  the 


Citrus  Botany,  Gross  Structure,  atid  Habits  of  Growth      47 


center  of  growth  being  crowded  close  to  the  bark  on  the 
upper  side.  This  curious  condition  is  entirely  normal  in 
the  lemon  and  greatly  strengthens  the  branches,  enabling 
them  to  carry  a  much  larger  load  without  breaking. 

There  are  two  sap  currents  in  the  trunk  and  branches, 
one  consisting  of  dissolved  mineral  matters  taken  from  the 
soil  water  by  the  roots,  which 
passes  up  through  vessels  in  the 
wood  to  the  leaves ;  and  an- 
other, consisting  of  elaborated 
plant  food,  and  other  complex 
substances,  which  passes  down 
through  the  inner  bark  and 
nourishes  every  growing  part, 
even  the  tips  of  the  longest 
roots.  It  should  be  remembered 
that  the  action  between  root 
and  leaf  is  reciprocal.  The 
most  remote  tip  of  the  longest 
root  must  await  the  return  of 
the  elaborated  sap  from  the 
leaves  before  it  is  able  to  grow 
a  fraction  of  an  inch.  For  sake 
of  emphasis  we  repeat :  the 
roots  of  a  plant  are  quite  as  de- 
pendent upon  the  leaves  for  elaborated  food  as  they  are 
upon  the  soil  for  raw  food,  for  roots  cannot  use  raw  mineral 
food.  That  the  downward  current  of  elaborated  sap  takes 
place  through  the  bark  is  proved  by  the  swelling  which 
occurs  just  above  the  point  of  constriction  when  a  label 
wire  is  overlooked  and  allowed  to  remain,  on  a  young  tree. 


Fig.   10.  —  Growth  rings  in  a 
flattened  brace  limb  of  lemon. 


4,S 


Citrus  Frtiif.'i 


Advantage  is  taken 
of  this  fact  in  the 
l)r()cess  known  as 
"ringing"  which  is 
chiefly  used  with 
grapes  and  pears.  A 
ring  of  bark  half  an 
inch  wide  is  removed 
from  the  small  branch 
which  bears  a  fruit 
cluster.  The  fruit 
and  leaves  continue 
to  draw  food  from 
the  roots  through  the 
wood,  but  as  the 
l)ranch  is  prevented 
from  returning  its  pro- 
portionate share  of 
elaborated  food  to 
the  trunk  and  roots,  it 
soon  accumulates  an 
extra  amount  which 
causes  the  fruit  to 
grow  to  an  unusually 
large  size.  By  this 
method  aNavelorange 

Fig.  11.  -  Result  of  exix'rinicnt  wlii.h  .shows  ^^^'^f  produCcd  which 
that  a  girdled  orange  tree  may  grow  new  weighed  3  j  poUnds 
bark  if  treated  in  time.      A,  untreated;  i  iio-      i 

js,  treated.  and  measured  18  inclies 

in  circumference.^ 
^Scientific  American,  Dec.  14,  1912,  p.  515. 


Citrus  Botany,  Gross  Structure,  and  Habits  of  Growth     49 

The  line  which  separates  the  two  currents  of  sap  is 
known  as  the  cambium  and  is  roughly  represented  by  the 
line  of  cleavage  when  a  strip  of  bark  is  pulled  away  from 
the  trunk.  It  is  on  this  line  that  growth  takes  place,  the 
cells  dividing  continually,  one  part  going  to  build  wood 
and  the  other  causing  a  thickening  of  the  bark. 

Citrus  trees  are  apt  to  form  large  quantities  of  giun  along 
the  line  of  the  cambium,  when  stimulated  by  the  growth 
of  fungous  parasites,  or  by  other  causes,  the  exact  nature 
of  which  are  not  clearly  understood. 

Many  trees  are  unable  to  grow  new  bark  direct  from  the 
cambium,  but  heal  over  wounds  by  pushing  new  tissue 
out  from  the  sides  of  the  wounds.  The  citrus  tree  will 
often  grow  new  bark  direct  from  cambium  laid  bare  by 
gophers  or  gum-disease.  Occasionally  a  tree  which  has 
been  entirely  girdled  will  grow  new  bark  and  recover. 
The  bark  of  citrus  trees  is  also  peculiar  in  that  it  retains 
some  green  matter  or  chlorophyll  and  continues  to  function 
as  a  leaf  until  the  tree  reaches  a  great  age. 

Leaves 

With  the  exception  of  Citrus  trifoliata,  all  citrus  trees 
are  evergreen ;  that  is,  the  bulk  of  the  leaves  do  not  fall 
before  the  new  leaves  have  expanded.  A  few  of  the  oldest 
leaves  may  fall  at  any  time  of  the  year,  but  the  })eriod 
of  heaviest  fall  is  in  April  and  May  after  the  spring  growth 
has  taken  place.  The  normal  life  of  an  orange  leaf  depends 
on  the  kind  of  wood  upon  which  it  is  borne.  Leaves  on 
the  fine  fruiting  brush  usually  remain  on  the  tree  for  about 
fifteen  months,  while  leaves  on  vigorous  upright  vegeta- 


50  Citrus  Fruits 

tive  growths  will  remain  green  and  in  flourishing  condi- 
tion for  three  and  even  four  years.  The  leaves  on  the 
trunks  of  nursery  trees,  if  protected  and  not  removed,  will 
usually  remain  for  several  years.  It  is  customary  to  re- 
move these  leaves  at  the  time  the  tree  is  dug  for  the  purpose 
of  reducing  transpiration. 

In  the  case  of  the  trifoliate  orange  the  leaves  fall  in  the 
autumn,  the  tree  remaining  bare  during  winter  and  until 
after  the  blooming  period  in  spring. 

Citrus  leaves  vary  in  shape  and  size  with  the  different 
species ;  the  pomelo  and  Seville  orange  having  broad  wings 
on  the  petioles,  while  the  sweet  orange  has  a  very  narrow 
wing  and  the  citron  none  at  all.  The  width  of  these  wings 
will  vary  a  good  deal,  being  wider  on  the  vigorous  shoots 
and  very  much  smaller  on  the  fruiting  brush.  The  edges 
of  the  sweet  orange  leaf  are  entire,  while  with  the  lemon  and 
lime  the  edges  are  indented  or  crenate.  Most,  if  not  all, 
of  the  stomata  or  breathing  pores  are  situated  on  the  under 
side  of  the  leaves,  and  this  is  a  distinct  advantage  when  the 
upper  surfaces  of  the  leaves  become  coated  with  dust  from 
the  roads  during  the  dry  season,  or  with  cement  dust  from 
near-by  cement  mills. 

One  striking  characteristic  of  all  citrus  leaves  is  the  pres- 
ence of  numerous  glands, w^hich  maybe  easily  seen  with  the 
unaided  eye,  although  they  do  not  project  above  the  sur- 
face of  the  leaf.  These  glands  are  filled  with  a  fragrant 
and  aromatic  oil  which  is  very  volatile  and  gives  to  the 
freshly  crushed  leaves  their  characteristic  odor.  This  odor 
varies  with  the  different  species.  One  method  of  distin- 
guishing between  sweet  and  sour  stock  seedlings  in  the 
nursery  is  by  recognizing  the  odor  of  the  crushed  leaves. 


Citrus  Botany,  Gross  Structure,  and  Habits  of  Growth     51 


Thorns 

Sharp,  slender  thorns  are  characteristic  of  most  kinds 
of  citrus  trees.  Seedhngs  of  the  sweet  orange  have  per- 
haps the  most  formidable  thorns  and  these  are  a  serious 
hindrance  in  harvesting  the  fruit  and  pruning  the  trees. 
The  trifoliate  orange  has  short,  thick  thorns  which  are  very 
numerous.  Certain  cultivated  varieties  are  practically 
free  from  thorns,  and  this  quality  adds  much  to  their 
popularity.  Thorns  are  borne  in  the  axils  of  the  leaves, 
and  their  size,  in  a  given  variety,  depends  largely  upon  the 
vigor  of  the  shoot  upon  which  they  occur,  being  long  on 
rapidly  growing  shoots  and  short  and  inconspicuous  on 
the  fruiting  brush.  The  Navel  orange  and  Eureka  lemon 
are  practically  thornless  varieties ;  yet  on  water-sprouts 
long  sharp  thorns  may  sometimes  appear. 

Thorns  are  objectionable  not  only  on  account  of  the 
difficulty  occasioned  in  picking  fruit,  but  also  on  account  of 
the  injury  done  to  the  fruit  itself.  When  the  wind  tosses 
the  branches  about,  the  fruit  is  stabbed  on  many  sides  by 
the  thorns,  giving  an  excellent  opportunity  for  inoculation 
and  consequent  fungous  decay.  In  dry  weather  when 
small  wounds  are  quickly  dried  (and  perhaps,  to  a  certain 
extent,  cauterized  by  the  escape  of  oil  from  the  broken  oil- 
cells)  there  is  less  decay  of  fruit  on  the  trees  from  this 
cause.  While  this  is  true,  the  constant  rubbing  or  pricking 
of  a  fruit  against  the  point  of  a  thorn  will  so  irritate  the 
rind  as  to  cause  a  very  ugly  callous  to  form  on  the  skin 
and  thus  ruin  the  market  value  of  the  fruit. 

There  is  a  widespread  belief  among  citrus  nurserymen 
and  others  that  thorns  may  be  largely  eliminated  from  any 


52  Citrus  Fruits 

variety  by  careful  selection  of  budwood  through  several 
bud  generations.  We  know  of  no  published  data  of  scien- 
tific experiments  to  determine  this  point  and  doubt  very 
much  whether  the  grounds  for  this  belief  are  sufficient. 
It  can  do  no  possible  harm  to  select  only  thornless  bud- 
wood  for  propagation,  and  where  this  happens  to  result 
in  the  separation  of  pure-line  mutants  which  vary  in  thorni- 
ness  much  good  may  be  done.  On  the  other  hand  it  is 
difficult  to  concei\e  of  how  progress  can  be  made  by  selec- 
tion within  the  pure-line. 

Flowers 

Citrus  flowers  are  large,  showy,  and  fragrant,  and  are 
borne  in  great  profusion.  They  are  mostly  waxy  white, 
although  in  the  lemon  and  citron  the  backs  of  the  petals 
are  tinged  with  purple.  The  flowers  are  mostly  perfect 
or  complete,  consisting  of  a  green  calyx  with  three  to  five 
lobes,  subtending  white  petals,  four  to  eight  in  number, 
which  are  thick,  fleshy,  and  covered  with  oil  glands.  The 
stamens  are  numerous,  twenty  to  sixty  in  number,  their 
filaments  (stalks)  being  more  or  less  united.  The  style 
and  stigma  are  large  and  conspicuous.  The  exudation  of 
white  mucilage  by  the  stigma  is  quite  copious,  as  is  also 
the  watery  nectar  in  the  base  of  the  flower  cup.  The 
pollen  is  golden  yellow  and  is  produced  in  abundance 
except  in  certain  varieties.  The  orange  has  flowers  borne 
in  cymes  on  shoots  of  the  current  year's  growth.  In  the 
case  of  the  lemon,  kumquat,  and  others,  the  new  growths 
are  sometimes  so  short  (the  leaves  appearing  as  mere 
bracts),  that  the  flowers  have  the  appearance  of  being 
borne  on  old  wood. 


Fic.  112.  —  Valencia  Drange  blossoms. 


54 


Citrus  Fruits 


The  flowers  of  the  orange  and  pomelo  appear  during 
April  and  early  May.  Occasionally  a  bunch  here  and  there 
or  even  an  entire  tree  may  bloom  at  some  other  season,  but 
the  fruits  from  such  off-season  blooms  will  usually  be  ab- 
normal in  shape  and  inferior  in  quality.  Lemons  bloom 
and  set  fruit  the  year  round  with  the  period  of  most  abun- 
dant bloom  coinciding  with  that  of  the  orange. 

Lemon  trees  are  peculiar  in  that  they  bear  flowers  of 
several  kinds.     Those  that  produce  fruit  are  perfect,  con- 


^^M 


Fig.    13. 


Lemon    blossoms    showing    perfect,    partly    aborted,    and 
aborted  pistils. 


taining  both  stamens  and  pistils.  There  are  other  flowers 
borne  by  the  same  tree  in  which  the  pistils  are  reduced  to  a 
mere  rudiment  while  the  stamens  are  large  and  well  de- 
veloped. Li  addition  to  these  there  are  certain  abortive 
buds,  observed  on  the  Eureka  lemon  chiefly,  in  which  the 
petals  do  not  develop  but  remain  closed,  the  stigma  forcing 
its  way  out  between  them.  Only  the  perfect  lemon  blos- 
soms set  fruit,  although  the  second  kind  mentioned  may 
aid  in  pollination.  Lemons  require  about  nine  months 
from  blossom  to  maturity  of  fruit.     A  few  fruits  will  come 


Citrus  Botany,  Gross  Structure,  and  Habits  of  Growth     55 

up  to  size  in  six  months,  while  some  will  remain  undersized 
for  a  year  and  finally  turn  yellow,  at  which  time  they  are 
picked  regardless  of  size. 


Pollination 

The  larger  number  of  fruits,  such  as  apples,  plums, 
grapes,  and  strawberries,  require  pollination  in  order  to  set 
fruit.  Some  kinds  of  citrus  fruits  require  pollination  in 
order  to  set  and  mature  fruit,  but  a  large  number  do  not. 
Many  forms  of  citrus  bear  parthenocarpic  or  seedless 
fruits,  and  with  these  pollination  is  not  only  unneces- 
sary, but  is  apparently  a  disadvantage,  inasmuch  as  it 
results  in  some  cases  in  the  formation  of  seeds  which 
are  objectionable. 

In  Florida  a  large  number  of  varieties  are  grown  com- 
mercially, and  as  most  of  them  contain  seeds  it  is  probable 
that  a  large  proportion  at  least  require  pollination  for  their 
best  development.  Florida  writers  are  strangely  silent  on 
this  point.  In  the  citrus  districts  of  the  Southwest  it  hap- 
pens that  the  five  varieties  chiefly  grown  —  Washington 
Navel  and  Valencia  oranges.  Eureka  and  Lisbon  lemons, 
and  Marsh  pomelo  — -  are  more  or  less  parthenocarpic. 
Those  kinds  which  contain  some  seeds,  as  the  Lisbon  lemon 
for  instance,  are  able  to  set  and  mature  fruit  without  polli- 
nation, which  results  merely  in  the  formation  of  seeds.^ 
The  Washington  Navel  orange  flowers  contain  no  pollen 
whatever  and  in  the  p]ureka  lemon  viable  pollen  is  rare 
except  at  certain  seasons,  yet  these  varieties  produce  quite 

^  Unpublished  Report  on  Pollination  Experiments  by  the 
Writer. 


56  Citrus  Fruits 

as  well  when  planted  in  solid  blocks  of  hundreds  of  acres 
far  from  other  varieties,  as  they  do  in  mixed  plantings. 

T.  Ikeda  ^  in  a  series  of  brilliant  experiments  has  shed 
much  light  on  this  interesting  subject.  His  })rincipal 
results  may  be  summarized  as  follows  : 

1.  Certain  varieties  of  oranges  reciuire  pollination  in 
order  to  set  fruit. 

2.  Certain  varieties  of  oranges  which  ordinarily  contain 
seeds  will  without  pollination  set  and  mature  a  small  num- 
ber of  parthenocarpic  fruits. 

3.  Many  varieties  of  oranges  are  uncongenial,  cross- 
pollination  being  followed  by  dropping  of  flow-ers  and 
young  fruit. 

4.  Cross-pollination  between  seed  bearing  and  parthe- 
nocarpic varieties  may  result  in  the  setting  and  maturing 
of  fruit  containing  viable  seeds,  provided  the  pollen  used 
is  that  of  a  congenial  variety. 

5.  Parthenocarpic  varieties  do  not  require  the  stimulus 
of.  pollination  in  order  to  set  and  mature  fruit. 

6.  The  pollen-tube  may  reach  the  ovule  as  soon  as  30 
hours  after  pollination.  Fusion  of  male  and  female  cells 
may  begin  48  hours  after  pollination.  Fertilization  is 
completed  in  from  48  to  72  hours  after  pollination. 

7.  In  the  Washington  Navel  and  Satsuma  oranges  the 
embryo-sacs  usually  disintegrate  instead  of  developing 
into  embryos  capable  of  being  fertilized. 

Occasionally  a  few  normal  embryo-sacs  are  produced 
in  both  Washington  Navel  and  Satsuma  oranges.^     Thus 

1  Tomochika  Ikeda,  "On  the  Parthenocarpy  of  Citrus  Fruits," 
Jour.  Sci.  Agr.  Soc.  Tokyo,  Vol.  63,  1904. 

^  The  factors  which  influence  the  frequency  of  occurrence  of 


Citrus  Botany,  Gross  Structure,  and  Habits  of  Growth     57 

a  few  seeds  may  be  prochicefl  provided  the  particular  fruits 
having  the  normal  embryo-sacs  happen  to  be  pollinated 
with  viable  pollen  from  congenial  varieties.  It  is  the 
remoteness  of  the  chance  of  this  occurring  under  ordinary 
field  conditions  that  accounts  for  the  comparative  seedless- 
ness  of  these  fruits.     Apparently  there  is  nothing  in  the 


Fig.  14 


Orange  flower  X  2      /;,  pi'^til ,    a,  stigma  ;    c,  style 
s,  stamen;  b,  anther;  c.  filament,  d,  riectai> 


ovary; 
a,  sepal;  /,  petal. 


structure  of  the  blossoms  of  either  the  Washington  Xavel 
or  the  Satsuma  orange  which  would  interfere  in  any  way 

normal  embryo-saes  have  not  been  fully  worked  out.  Experi- 
ments now  being  carried  on  by  the  writer  seem  to  indicate  that 
the  climate  factor  is  most  important.  Normal  embryo-sacs  of 
Washington  Navels  occur  much  more  frequently  at  Riverside 
than  at  Whittier  where  they  are  very  rare.  For  this  reason  plant- 
breeders  wishing  to  use  the  Navel  as  a  maternal  parent  in  cross- 
breeding work  may  e.xpect  greater  results  from  crosses  made  at 
Riverside  or  other  interior  points. 


58  Citrus  Fruits 

with  the  germination  of  pollen  or  normal  extension  of  the 
pollen  tube. 

The  occasional  seeds  sometimes  found  in  Washington 
Navel  oranges  as  they  occur  on  the  market  are  undoubt- 
edly due  to  cross-pollination  with  some  other  variety  by 
insects  or  other  agencies.  The  question  as  to  what  would 
be  the  result  should  these  seeds  be  planted  and  reared  to 
maturity  has  already  been  answered  by  the  experiment 
of  W.  H.  Backus  of  Riverside,  a  part  of  whose  report  is 
here  quoted.^ 

"Some  years  ago  when  almost  every  one  was  budding 
over  their  seedlings  to  Navels,  I  thought  the  result  might 
be  too  many  early  oranges.  At  that  time  I  did  not  think 
the  Valencia  the  most  desirable  late  orange,  as  a  Cali- 
fornia orange  should  have  high  color  in  addition  to  being 
late. 

"To  obtain  this  desirable  feature,  together  with  high 
color  quality  and  medium  size,  I  tried  hybridizing  the 
Mediterranean  Sweet  on  the  Washington  Navel,  three 
successive  seasons,  cutting  all  the  oranges  when  ripe  for 
seed.  Altogether  I  secured  about  fourteen  hundred  seeds 
that  were  well  matured. 

"  These  were  planted  in  the  seed  bed,  but  owing  to  my 
lack  of  experience  in  nursery  work,  a  large  percentage  of 
the  little  trees,  of  the  first  and  second  plantings,  died  when 
about  three  inches  high.  One  peculiar  thing  to  me  was 
that  over  90  per  cent  of  the  seeds  sprouted  from  two  to  six 
shoots  each.^ 

"The  young  nursery  stock  was  much  neglected  for  three 

1  Riverside  Daily  Press,  March  2,  1909. 

2  An  interesting  record  of  polyembryony. 


Citm.s  Botany,  Gross  Structure,  ami  Habits  of  Growth     59 

or  four  years,  when  I  took  buds  from  the  most  thrifty  to 
bud  over  old  trees.  Although  these  buds  stand  10  to  18 
feet  apart  in  an  old  grove,  still  they  made  a  rapid  growth, 
equal  to  a  straight  seedling,  and  are  now  about  25  feet 
high. 

"The  disappointment  came  when  they  began  to  bear. 
Many  were  of  no  value  at  all ;  the  best  w^ere  early,  some 
apparently  earlier  in  ripening  than  the  Navel,  but  generally 
of  good  color,  sweet  and  seedless.  The  trees  were  exceed- 
ingly thorny  and  some  much  more  thrifty  than  others; 
many  appeared  to  be  good  bearers  while  others  were  shy 
or  very  late  in  coming  into  bearing.  Consequently  al- 
most all  have  been  rebudded  or  dug  up." 


Polyemhryony 

A  peculiar  thing  about  citrus  seeds  is  the  fact  that  a 
variable  proportion  of  them  will  give  rise  to  from  one  to 
ten  distinct  seedlings  each.  This  is  known  as  polyem- 
brj'ony  and  is  due  to  a  number  of  adventitious  embryos 
appearing  in  the  embryo-sac.  Some  of  these  bud  embryos 
may  develop  into  seedling  plants  along  with  the  sexual 
embryo  which  requires  fertilization  in  order  to  develop. 
This  explains  why  seedlings  in  the  seed  bed  often  appear  to 
grow  in  bunches  even  though  the  seeds  were  planted  sepa- 
rately. As  only  one  of  the  seedlings  arising  from  any 
given  seed  is  the  result  of  pollination  and  fertilization,  it 
follows  that  the  others  must  be  vegetative  seedlings,  and, 
in  case  the  seed  is  from  a  known  variety,  will  reproduce 
the  variety  true  from  seed  without  the  necessity  of  bud- 
ding.    It  is  impossible,  however,  to  distinguish  the  sexual 


60 


Citrus  Fruits 


seedling  from  the  others  in 
the  early  years  of  growth, 
except  in  the  case  of  crosses 
between  forms  which  have 
very  differently  shaped 
leaves.  It  would  be  imprac- 
ticable to  propagate  Navels 
true  from  seed  on  account 
of  the  rarity  of  seeds  and  the 
necessity  of  pollinating  the 
flowers,  but  it  would  be  a 
simi)le  matter  with  seed}^ 
varieties  were  it  not  for  the 
difficultv  above  mentioned. 


Structure  of  the  Fruit 

According  to  Bonavia,^ 
the  citrus  fruit  consists  mor- 
phologically of  two  whorls 
of  transformed  leaves,  one 
going  to  make  the  rind  and 
the  other  to  make  the  group  of  carpels  or  sections  of 
the  fruit.  Each  carpel  is  supposed  to  be  a  leaf  folded 
over  in  such  a  way  that  its  two  edges  meet  in  the 
center  on  the  axis  of  the  fruit  and  along  which  the 
seeds  are  borne.  The  number  of  these  sections  or 
divisions  varies  considerably  even  in  the  same  variety. 
The  little  juice  sacks  or  vesicles  within  each  carpel  are 
supposed  to  be  transformed  oil  glands  of  the  leaves.  As 
^  E.  Bonavia,  "Oranges  and  Lemons  of  India,"  Vol.  I. 


Fig.  15.  —  Polyembryony.    Two 
orange  seedlings  from  one  seed. 


Citnt.'i  Botany,  (Iro.s.s  Structure,  and  Ilabit.s  of  (Growth      01 

varieties  of  double  flowers  are  formed  by  the  growth  of  an 
additional  whorl  of  petals,  so  varieties  of  double  fruits 
may  come  about  l)y  the  growth  of  additional  whorls  of 
carpels,  and  this  is  what  has  taken  place  in  the  case  of  the 
Navel  orange,  as  any  one  may  obser\e  by  making  a  num- 
ber of  thin  transverse  sections  through  the  apical  end  of  a 
Navel  orange,  and  studying  these  sections.  The  vesicles 
in  citrus  fruits  are  multicellular  and  are  attached  by  a 
stalk  in  nearly  all  cases  to  the  outer  wall  of  the  carpel, 
only  a  very  few  being  attached  to  the  sides.  These  vesi- 
cles are  fed  directly  by  fibro-vascular  bundles  branching 
from  the  stem  and  running  through  the  white  spongy 
tissue  which  composes  the  inner  part  of  the  rind.  The 
seeds  vary  in  number  from  none  as  in  the  Navel  to  fifty 
or  more  in  the  trifoliata.  They  are  attached  to  the  inner 
edges  of  the  carpels. 

Citrus  fruits  in  common  with  other  fruits  are  not  to  be 
considered  as  so  much  dead  matter  after  they  are  plucked 
from  the  tree.  They  live  and  breathe  (transpire)  for  many 
months.  They  also  lose  water  and  shrink  in  size  and 
weight  as  a  result  of  giving  oft'  carbon  dioxide  and  water 
vapor.  If  protected  from  infection  by  decay-producing 
organisms,  oranges  or  lemons  will  keep  one  year  or  more, 
when  kept  moist  and  cool,  but  ^^'ill  eventually  die  and 
collapse  from  enzymatic  fermentation.  If  they  are  al- 
lowed to  lose  moisture,  they  will  dry  up  into  balls  as  hard 
as  wood.  An  understanding  of  the  vital  processes  going 
on  in  citrus  fruits  is  highly  important  in  connection  with 
the  curing  of  lemons  and  pomelos.     (See  Chapter  XVI.) 

Chemistry  of  the  Fruit.  —  Citrus  fruits  from  the  same  tree 
may  vary  much  in  their  composition.     Commercial  Cali- 


62 


Citrus  FruiU' 


Analyses  of  California  Oranges  and  Lemons 
(From  Bull.  No.  93,  Univ.  Cal.  Agr.  Exp.  Station) 


A.    Proximate  Analyses 

Wash. 

Med. 

Paper 

Malta 

Eureka 

Name  op  Variety 

Navel 

Sweet 

Rind 

Blood 

Lemon 

Average  weight  in  grams 

300 

202 

138 

177 

104 

Water,  per  cent    .     .     . 

85.82 

85.19 

84.76 

85.68 

83.82 

Organic  matter,  per  cent 

13.95 

14.32 

14.77 

14.39 

15.61 

Ash,  per  cent  .... 

.42 

.47 

.46 

.42 

.56 

Rind,  per  cent      .     .     . 

28.4 

27.0 

19.2 

31.0 

32.0 

Pulp  less  juice,  per  cent 

27.7 

24.0 

25.9 

24.0 

24.5 

Seeds,  per  cent     .     .     . 

0.8 

1.6 

0.12 

Number  of  ce.  of  juice, 

average   

107 

86 

65.4 

71 

38 

Solid  contents  of  juice 

by  spindle    .... 

12.80 

12.60 

12.10 

13.55 

11.90 

Total  sugars  in  juice  (by 

copper  inversion),  per 

cent 

9.92 

9.70 

8.71 

10.30 

2.08 

Cane  sugar  in  juice  (by 

polariscope),  per  cent 

4.80 

4.35 

3.48 

5.85 

0.57 

Citric  acid,  per  cent 

1.02 

1.38 

1.35 

1.61 

7.66 

Nitrogen  in  fresh  fruit, 

per  cent        .... 

0.211 

0.154 

0.228 

0.168 

0.151 

Albuminoids     in     fresh 

fruit,    equivalent    to 

nitrogen,  per  cent      . 

1.31 

0.96 

1.43 

1.05 

0.94 

Analyses  of  Ash 


Lemons 


Potash  (K2O),  per  cent 

Soda  (NaaO) 

Lime  (CaO) 

Magnesia  (MgO) 

Peroxide  of  iron  (FeoOs  and  alumina 

(Al,03) 

Br.  oxide  manganese  (Mg304)    .     .     . 

Phosphoric  acid  (PoOs) 

Sulphuric  acid  (SO.s) 

Silica  (SiO.) 

Chlorine  (CI) 


48.26 

76 

29.87 

4.40 


Citrus  Botany,  Gross  Structure,  and  Habits  of  Growth    63 

foniia  oranges  contain  about  30  per  cent  rind  and  40  per 
cent  juice  when  freshly  picked  from  the  trees.  The  percent- 
age of  juice  increases  as  the  fruit  is  cured  for  the  water  in 
the  rind  is  lost  first  by  evaporation  and  transpiration. 
California  Navel  oranges  will  analyze  about  10  per  cent 
total  sugars,  4^  per  cent  of  which  is  cane  sugar,  the  re- 
mainder being  a  mixture  of  other  fruit  sugars.  Navel 
oranges  contain  about  1  per  cent  of  citric  acid.  Lemons 
contain  about  2  per  cent  total  sugars,  of  which  ^-  per 
cent  is  cane  sugar,  and  7|  per  cent  of  citric  acid. 

Harvest  Season 

In  California,  oranges  and  lemons  are  harvested  through- 
out the  year.  The  orange  season  begins  with  Navels  about 
November  15  in  central  California  and  moves  south- 
ward. The  last  Navels  are  shipped  from  southern  districts 
about  May  1.  During  May  and  a  part  of  June  miscel- 
laneous varieties  including  seedlings  and  some  late  Navels 
are  gathered  and  shipped.  The  Valencia  harvest  begins 
in  central  California  in  June  and  continues  southward, 
the  last  of  the  crop  going  forward  from  the  coast  districts 
in  November  and  thus  overlapping  the  Navel  crop  of  the 
next  season. 

Lemon  trees  are  picked  over  once  each  month  or  about 
ten  times  a  year,  the  trees  bearing  fruit  in  all  stages  of 
growth  from  the  blossom  to  the  mature  fruit  at  all  times. 
Lemons  should  not  be  allowed  to  ripen  on  the  tree .  They 
should  be  picked  when  they  have  reached  a  diameter  of 
2yq  inches  in  summer  and  2^^  inches  in  winter  and 
spring,  regardless  of  color. 


64  C'lfrus  Fruits 

I.oiifirrifi/ 

Citrus  trees  are  naturally  lonji;  lived.  If  planted  on 
deep,  rich  soil  and  given  good  care,  they  should  bear  profit- 
ably for  fifty  years  or  more.  IVIuch  has  been  said  in  print 
about  a  natural  limit  of  profitableness  in  the  case  of  the 
Navel  orange.  This  limit  is  sometimes  placed  at  twenty- 
five  years.  The  writer  believes  this  to  be  a  mistake. 
Navel  oranges  as  well  as  other  kinds  of  citrus  will  live 
and  produce  generous  crops  to  a  very  great  age,  provided 
they  are  growing  on  deep,  fertile  soil  and  are  well  cared 
for. 


CHAPTER  IV 
VARIETIES 

As  stated  in  a  previous  chapter,  the  first  oranges  grown 
in  CaHfornia  were  seedhng  sweet  oranges.  Unhke  the 
apple  and  peach,  the  sweet  orange  will  come  fairly  true 
from  seed,  the  fruit  from  practically  all  seedlings  being 
marketable.  Each  tree,  however,  varies  from  its  neigh- 
bors in  many  minor  characters,  such  as  size,  producti\e- 
ness,  season  of  ripening,  seed  content,  flavor,  and  shipping 
qualities.  The  fruit  from  an  orchard  of  seedlings  lacks 
uniformity,  which  is  one  of  the  chief  requisites  of  a  com- 
mercial fruit  product.  Seedling  trees  grow  very  large, 
so  large  in  fact  that  it  is  expensive  to  gather  the  fruit  and 
often  difficult  or  impracticable  to  inclose  the  trees  in  fumi- 
gating tents.  For  these  and  other  reasons  the  old  seedling 
orchards  have  been  gradually  cut  down  and  replaced  by 
budded  trees  or  top-worked  to  improved  varieties,  until 
at  the  present  time  comparatively  few  remain. 

During  the  transition  from  seedling  to  budded  orchards 
the  question  as  to  which  of  the  many  varieties  available 
would  prove  the  most  i)rofitable  was  a  favorite  subject  for 
discussion. 

By  1885,  enterprising  nurserymen  had  introduced  most 
of  the  important  varieties  of  the  world,  and  these  were 
F  65 


66  Citrus  Fruits 

tested  alongside  many  local  seedlings  of  special  merit. 
Probably  as  many  as  one  hundred  diflFerent  varieties  were 
given  trial.  At  the  early  citrus  fairs  such  imported  vari- 
eties as  the  Du  Roi  and  Pernambuco  were  to  be  seen  exhib- 
ited side  by  side  with  California  productions  such  as 
Asher's  Best  and  Bostram's  Prize.  The  elimination  of  the 
less  profitable  varieties  took  place  rather  rapidly,  and  by 
the  year  1900  we  find  the  Washington  Navel  orange  oc- 
cupying more  land  than  all  other  varieties  of  oranges  com- 
bined. At  this  time  the  two  fittest  survivors,  the  Navel 
and  Valencia,  dominated  the  field. 

DESCRIPTIONS   OF   VARIETIES   OF   ORANGES 

Washington  Navel  (Bahia,  Riverside  Navel).  — Form 
rounded,  slightly  tapering  at  apex,  somewhat  longer  than 
wide ;  small  umbilicus  ;  size  variable,  2|  to  .3|  inches  in  di- 
ameter ;  color  orange  when  grown  near  coast,  deep  orange 
when  grown  in  interior  valleys ;  juice  abundant,  orange 
colored ;  flavor  excellent,  acid  and  sugar  well  blended ; 
vesicles  large,  spindle  shaped  ;  skin  |  to  |  inch  thick,  varying 
from  smooth  to  pebbly ;  size  of  secondary  orange  under 
umbilicus  variable,  often  f  inch  in  diameter.  Seeds  none, 
except  in  very  rare  cases. 

Tree  semi-dwarf,  ^^gorous,  very  precocious,  prolific, 
thornless  or  with  thorns  only  on  vigorous  shoots  ;  appearance 
of  blossoms  normal  except  for  the  fact  that  the  anthers  are 
cream  colored  and  contain  no  pollen  whatever.  Introduced 
from  Bahia,  Brazil,  1870,  by  the  late  William  Saunders,  then 
in  charge  of  U.  S.  Government  propagating  grounds  at 
Washington,  D.  C. 

The  Washington  Navel  well  deserves  the  title  "King  of 
Oranges."     Under  the  climatic  conditions  of  California  and 


Varieties 


67 


Arizona  this  variety  approaches  very  nearly  to  the  ideal 
orange.  The  dry  air,  bright  sun,  and  cool  nights,  operating 
in  conjunction  with  the  skill  of  the  grower  and  packer  upon 
the  natural  qualities  and  character  of  this  orange,  have  made 
it   the   greatest   commercial    orange   in    the   world.     These 


Fig.  16.  —  The  earliest  known  illustration  of  a   Navel  orange.      From 
Ferrarius'  "  Hesperides,"  164G. 


thornless  trees  combine  heavy  and  regular  yields  with  a 
high  color  of  the  fruit,  a  silkiness  of  texture,  and  a  general 
finish  which  is  almost  perfect.  It  is  solid  and  full  of  juice 
of  exceptionally  high  flavor,  but  it  is  entirely  lacking  in 
seeds.  It  is  a  very  good  keeper  and  travels  well  to  the  most 
distinct  markets.     It  possesses  moreover  a  natural  trade- 


68  Citrus  Fruits 

mark,  in  the  shape  of  a  navel-like  mark,  which  is  beyond 
imitation  and  which  is  of  great  market  value.  More  than 
eight  million  boxes  of  Washington  Navels  are  now  being 
grown  and  shipped  out  of  California  annually,  and  the  prices 
received  are  encouraging  a  rapid  increase  in  acreage. 

In  California,  the  Washington  Navel  reaches  its  highest 
development  in  quality  on  the  gravelly  soils  of  the  foothills 
in  the  warmer  interior  valleys.  The  yield,  however,  is  not  as 
heavy  as  it  is  near  the  coast,  where  the  fruit  tends  to  ripen 
later.  On  the  deep  heavy  soils  of  the  coast  country,  the 
skin  tends  to  be  somewhat  thicker  with  a  rougher  surface 
and  paler  color. 

One  characteristic  of  the  W^ashington  Navel  is  its  tendency 
to  sport  or  throw  out  occasional  l)ranches  bearing  fruit  of  a 
different  type.  By  far  the  larger  number  of  these  sports 
are  retrogressions,  and  careless  cutting  of  bud -wood  for  prop- 
agating purposes  from  trees  containing  such  sports  has  re- 
sulted in  a  great  lack  of  uniformity  in  existing  orchards. 
Occasionally  sports  are  found  which  possess  some  character 
of  supposed  value,  and  by  the  propagation  of  these  new 
varieties  have  appeared.  Among  such  offspring  we  note 
the  following :  Thomson,  Buckeye,  Na^'elencia,  Nugget,  and 
Australian. 

Thomson. — Fruit  of  medium  size;  skin  thin  and  very 
smooth  in  texture  ;  ripens  early.  The  quality  of  the  Thom- 
son is  somewhat  inferior  to  the  Washington  Navel,  but  it 
has  a  superior  appearance.  For  certain  markets  in  some  large 
cities  where  appearance  rather  than  qiuility  determines 
demand,  it  commands  a  premium  of  from  twenty-five  to 
fifty  cents  a  box  over  the  Washington  Navel.  For  this 
reason,  it  is  being  grown  on  an  increasing  commercial  scale. 

The  Thomson  was  introduced  by  A.  C.Thomson  of  Duarte, 
Los  Angeles  County,  about  1891,  and  is  generally  thought 


Varieties  69 

to  be  a  bud  sport  from  the  Washington  Navel.  Consider- 
ing the  story  told  by  Mr.  Thomson  of  his  method  of  pro- 
ducing this  form,  it  is  possible  that  it  may  be  a  perielinal 
chimera  ! 

Buckeye. — Fruit  medium  in  size  with  peculiar  bands  or 
ridges  of  deeper  orange  color ;  skin  smooth  and  of  fine 
texture ;  ripens  early.  Introduced  by  R.  M.  Teague  at 
San  Dimas,  California. 

Navelencia.  —  Fruit  medium  to  large,  smooth  and  thin- 
skinned  ;  season  said  to  be  somewhat  later  than  Washington 
Navel ;  more  susceptible  to  frost  than  Washington  Navel. 
Originated  by  A.  C.  Thomson,  at  Duarte,  California. 

Nugget.  —  Fruit  oblong,  medium  in  size,  smooth,  solid,  and 
thick  skinned,  often  with  an  objectionable  but  characteristic 
crack  or  slit  in  the  skin  on  one  side  ;  young  twigs  slender 
and  willowy,  tree  umbrageous  with  very  brittle  wood. 
Originated  by  J.  P.  Englehardt  at  Glendora.  Introduced 
by  R.  M.  Teague  at  San  Dimas,  California. 

Australian.  —  Fruit  very  variable,  rough,  coarse ;  navel 
often  closed ;    skin  thick,   especially  near  stem  end.     Tree 


Fiii.  17.  —  One  type  of  Australian  Navel  orange. 


70  Citrm  Fruits 

large  with  upright,  open  growth,  sliy  hearer.  Strictly 
speaking,  there  is  no  such  thing  as  the  Australian  Navel. 
The  term  is  a  misnomer  in  the  same  sense  as  the  term  English 
walnut  is  when  applied  to  the  Persian  walnut.  Tn  common 
usage,  however,  the  name  applies  to  a  certain  rough-fruited 
and  shy-l)earing  sport  of  the  Bahia  Navel,  which  was  un- 
wittingly introduced  into  California  from  Australia  in  an 
effort  to  secure  the  true  Bahia.  Some  persons  go  further 
and  call  any  undesirable  sport  an  Australian,  thus  using  the 
term  as  an  adjective  rather  than  as  a  noun.  Some  other 
persons  apply  the  term  x\ustralian  to  the  rank  growing 
wood  resulting  from  water  sprouts  in  the  tops  of  the  trees, 
which  tend  to  produce  coarse,  rough  fruit.  This  latter  is 
clearly  an  improper  use  of  the  term. 

Valencia.  —  Form  oblong,  somewhat  flattened  with  de- 
pressed ring  at  apex,  tapering  toward  base ;  size  medium, 
color  pale  orange  deepening  with  maturity ;  skin  smooth  or 
slightly  pebbled,  thin  but  tough ;  juice  plentiful,  flavor  sub- 
acid ;  seeds  variable,  sometimes  three  to  six,  often  none ; 
season  late,  from  June  to  November.  Tree  large,  vigorous 
grower,  prolific,  thorns  few  and  small. 

The  Valencia  hangs  on  the  tree  well  during  the  summer  but 
in  interior  valleys  it  is  apt  to  turn  green  again  in  late  summer. 
When  grown  in  such  situations,  it  should  be  harvested  in 
May  and  June.  In  deep  heavy  soils  near  the  coast,  it  can 
safely  lie  held  till  November  or  December. 

This  famous  orange  originated  in  the  Azores.  Thomas 
Rivers,  the  English  nurseryman,  imported  it,  with  other 
varieties,  from  the  Azores  into  English  glass-houses  and  first 
catalogued  it  in  1865  under  the  name  "Excelsior."  S.  B. 
Parsons,  a  Long  Island  nurseryman,  bought  trees  from  Rivers 
and  brought  them  to  America  about  1870.  He  kept  them  in 
his  greenhouse  for  several  years  and  then  moved  them  to 


Varieties  71 

his  nursery  near  Palatka,  Florida.  Parsons  sold  some  of 
these  trees  to  E.  H.  Hart,  of  Federal  Point,  Florida,  who 
gave  the  variety  the  name  "Hart's  Late"  or  "Hart's  Tar- 
diff."  Fruit  was  first  exhibited  before  the  Florida  Fruit 
Growers'  Association  on  April  25th,  1877. 

A.  B.  Chapman,  of  San  Gabriel,  California,  imported  a 
number  of  varieties  of  citrus  from  Thomas  Rivers  al)out  1870- 
72.  One  variety  labeled  Navel,  turned  out  not  to  be  a  Navel, 
but  of  distinct  value  on  account  of  its  ripening  very  late  in 
the  season  after  other  varieties  were  off  the  market.  Finally, 
at  the  suggestion  of  a  Spanish  laborer,  Mr.  Chapman  called 
the  orange  "Valencia  Late"  and  many  trees  were  propa- 
gated and  sold  under  this  name. 

California  nurserymen  early  secured  stocks  of  Hart's 
Tardiff  from  Florida,  and  many  thousands  of  trees  were 
planted.  When  it  became  evident  that  these  were  the 
same  as  the  Valencia,  the  latter  name  was  adopted  and 
is  now  used  exclusively  in  California.  This  name  has 
become  so  well  fixed  in  the  trade  and  market  reports  as  well 
as  in  the  every-day  speech  of  the  people  that  it  is  idle  to 
attempt  to  change  the  name  in  order  to  conform  to  the  rules 
of  horticultural  nomenclature. 

The  fame  and  popularity  of  the  Valencia  orange  has  been 
greatly  advanced  in  California  by  the  wonderful  record  made 
by  a  superb  orchard  of  this  variety  owned  by  C.  C.  Chapman 
at  FuUerton  in  Orange  County. 

Mediterranean  Sweet.  — Form  round  or  somewhat  flattened  ; 
size  medium  to  small ;  color  deep  orange  ;  skin  of  fine  texture  ; 
juice  abundant,  very  sweet ;  seeds  few,  small ;  season  April 
to  May ;  tree  semi-dwarf  with  small  narrow  leaves  very 
thickly  set,  almost  thornless. 

Introduced  and  renamed  by  T.  A.  Garey  of  Los  Angeles 
about  1870.     Secured  from  Thomas  Rivers  of  England. 


72  Citrus  Fruits 

Paper  Rliid  (Paper  Rind  St.  Michael). — Form  round; 
size  small,  solid  with  high  specific  gravity;  color  yellow,  or 
pale  orange ;  skin  very  thin  and  very  smooth ;  jnice  ai)un- 
dant,  colored,  with  rich  vinous  flavor;  seeds  three  to  six  in 
number,  medium  sized  ;  season  March  to  May ;  tree  semi- 
dwarf,  medium  thorny,  very  productive.  Introduced  from 
the  island  of  St.  Michael. 

Rtihif  (Blood).  —  Form  round  or  slightly  ol)long,  sometimes 
navel  marked  ;  size  medium  ;  color  deep  orange  or  reddish 
when  fully  matm-e  ;  skin  smooth  ;  juice  deep  orange  in  color 
changing  to  red  as  fruit  matures  ;  flavor  very  rich  and  vinous  ; 
seeds  many ;  season  March  and  April,  tree  of  medium  size, 
compact  growth,  almost  thornless.  Imported  from  Mediter- 
ranean districts. 

Jaffa.  —  Form  round  ;  size  medium  ;  color  deep  orange  ; 
skin  smooth  or  slightly  pel:)bled  ;  juice  abundant  and  of 
excellent  quality  ;  seeds  many,  large  ;  season  March  to  May  ; 
tree  medium  sized,  more  resistant  to  cold  than  most  other 
sweet  oranges,  almost  thornless.  Imported  from  Palestine, 
where  it  is  largely  grown. 

Joppa.  —  Form  oblong,  slightly  shouldered  ;  skin  thin, 
somewhat  pebbled  ;  juice  abundant,  sweet,  and  of  fine  flavor  ; 
seeds  few  or  none  ;  season  March  to  July  ;  tree  large,  thorn- 
less. Originated  in  1877  by  A.  B.  Chapman  of  San  Gabriel, 
California,  from  seed  secured  from  Joppa,  Palestine. 

Crafton  (Crafton  Late).  —  A  late  seedling,  originated  by 
Myron  H.  Crafts,  several  large  budded  orchards  of  which 
are  still  in  bearing  in  the  vicinity  of  Crafton,  California.  It 
is  marketed  during  May  and  often  brings  very  good  prices. 

LEMONS 

In  the  early  days  of  the  industry  a  large  number  of  Euro- 
pean varieties  were  tested,  but  few  were  found  suitable  to 


Varieties  73 

the  California  conditions.  Many  seedlings  were  raised  also, 
most  of  Avhich  proved  disappointing  in  some  important 
respect.  At  present  new  plantings  are  limited  chiefly  to  two 
varieties,  the  Eureka  and  the  Lisbon.  While  a  few  old 
orchards  of  VilUifrancas  are  still  maintained,  but  few  are 
being  planted.     The  Eureka  is  rapidly  gaining  in  popularity 


Fig.  is.  —  Eureka  lemon,  uncured. 

over  the  Lisbon  and  it  appears  that  this  will  soon  be  the 
only  variety  planted  on  a  large  scale. 

Eureka.  —  Form  oblong,  apex  nippled,  base  tapering  ;  size 
medium ;  rind  smooth,  glossy,  sweet ;  juice  abundant, 
clear,  strongly  acid,   flavor  good ;    seeds  few,   often  none. 


74  Citrus  Fruits 

J.  H.  Needham,  in  an  essay  before  the  Pomological  Society 
at  Covina  in  1898,  says  :  "The  advantages  of  the  Eureka  are 
its  comparative  freedom  from  thorns,  its  tendency  to  early 
bearing,  and  when  properly  trained  to  enormous  crops  when 
it  comes  into  full  bearing,  and  its  continuous  blooming  and 
setting  of  lemons  all  the  year,  especially  in  sections  com- 
paratively free  from  frost.  The  objections  are  its  tendency 
to  set  its  fruit  on  the  tips  of  the  branches,  and  the  inclination 
to  grow  long  canes  with  but  few  laterals  and  to  drop  its  leaves 
on  the  long  canes  or  branches,  thus  leaving  the  limbs  and 
fruit  too  much  exposed  to  the  hot  rays  of  the  sun  in  the  heated 
term  of  summer." 

The  Eureka  lemon  originated  from  a  seed  planted  about 
1870  by  C.  R.  Workman  in  Los  Angeles.  Workman  and  Pres- 
ton began  to  propagate  it,  but  later  sold  all  the  stock  to  Thomas 
A.  Garey,  of  Los  Angeles,  who  propagated  it  extensively  and 
sold  it  under  the  name  Eureka. 

Lisbon.  —  Form  oblong  or  obovate,  apex  oblique,  nippled 
wath  a  characteristic  crease  to  one  side  of  the  nipple,  base 
tapering  sharply  to  calyx,  which  is  large ;  rind  thin,  smooth, 
sweet ;  juice  abundant,  clear,  and  strongly  flavored ;  seeds 
few,  sometimes  none ;  tree  large,  a  strong,  vigorous  grower, 
foliage  thickly  set,  not  precocious,  very  thorny. 

The  Lisbon  bears  its  fruit  uniformly  throughout  the 
tree.  The  heavy  foliage  protects  the  fruit  from  sunburn. 
The  tendency  is  to  bear  one  large  crop  maturing  in  winter, 
with  a  small  amount  of  summer  fruit.  Introduced  from 
Europe. 

Villafranca.  — "  Form  oblong,  slightly  pointed  at  the 
blossom  end,  rind  thin,  without  any  trace  of  bitterness ; 
acid  strong,  juicy  ;  nearly  seedless.  Tree  almost  thornless, 
branches  spreading  and  somewhat  drooping,  foliage  very 
abundant,    which    protects    the   fruit   from    sunburn.     The 


Varieties  75 

tree  is  a  strong  grower  and  is  considered  less  susceptible  to 
cold  than  most  varieties.     Introduced  from  Europe. 

"The  advantages  claimed  for  the  Villafranca  are  that  it 
makes  a  more  compact  tree  and  bears  its  fruit,  more  uni- 
formly over  the  entire  tree,  but  it  requires  at  least  one  year 
longer  to  come  into  bearing,  and  tlie  fruits  on  young  trees 


are  shorter  when  they  have  the  requisite  diameter  for  picking 
than  either  the  Eureka  or  the  Lisbon."  ^ 

Other  varieties  still  to  be  found  in  old  orchards  and  collec- 
tions are  Bonnie  Brae,  Genoa,  Sicily,  Messina,  and  Milan. 

POMELOS 

Marsh.  —  Form  flat  or  obovate ;    size  small  to  medium  ; 
color  light  yellow ;  rind  smooth,  variable  in  thickness ;  juice 
'  Lelong,  "Culture  of  the  Citrus  in  California,"  p.  1G7. 


76 


Citrus  Fniit.t 


Fig.  20.  —  Seedless  pomelo,  flowers  and  fruit.     From  Volckamer's 
"  Hesperides,"  1708. 

abundant ;  flavor  fair ;  pith  large,  open ;  seeds  none  or  one 
to  six ;  season  March  to  July  or  later ;  hangs  on  trees  well 
all  summer. 

According  to  Hume/  this  variety  was  introduced  by  C.  M. 
1  "  Citrus  Fruits  and  Their  Culture,"  p.  120. 


Varieties  77 

Marsh  of  Lakeland,  Florida,  about  1895  or  1896.  The  original 
tree  was  a  seedling  growing  in  Lakeland,  and  was  at  the 
time  of  the  freeze  fully  sixty  years  old. 

The  Marsh  is  the  chief  variety  of  pomelo  grown  commer- 
cially in  California  and  Arizona,  although  the  following  may 
be  occasionally  met  with  and  are  doubtless  deserving  of  a 
wider  planting.  While  seedlessness  is  a  very  desirable 
character  in  a  fruit,  it  should  not  be  allowed  to  outweigh  such 
characters  as  flavor,  juiciness,  and  quality.  California  is  in 
need  of  a  variety  of  pomelo  better  suited  to  the  conditions 
than  any  now  available. 

Nectar  {Duarte  Seedling).  ■ — ^  A  seedling  tree  brought  from 
Florida  and  fruited  at  Duarte,  California.  The  fruit  is 
round  and  solid  with  smooth  skin  of  pale  yellow  color.  The 
seeds  are  few  and  the  flavor  excellent. 

Duncan.  —  A  flat  fruit  with  rather  thick  skin  and  flesh 
of  grayish  green  color,  seeds  few,  season  late,  quality  good. 
Introduced  from  Florida. 

Triumph.  —  A  fine-appearing  fruit  and  full  of  juice  as 
well  as  seeds,  of  which  there  are  many.  Somewhat  lacking 
in  flavor. 

Imperial.  —  Size  medium  to  large,  rind  very  smooth, 
medium  thin,  and  of  fine  texture  ;  little  rag  ;  juice  abundant 
and  of  fine  aromatic  flavor.  R.  M.  Teague  says  of  this 
variety  :  "  It  is  one  of  the  best  keepers  and  shippers.  The 
tree  is  a  strong  upright  grower  and  a  heavy  cropper." 

Colton  {Colton  Terrace).  —  A  seedling  grown  at  Colton, 
California.  Size  medium  to  large,  heavy,  subacid,  and  deli- 
cately l)itter  ;  seeds  many  ;  skin  smooth  ;  oil  cells  very  small ; 
light  lemon  color,  turns  slightly  orange  color  when  mature. 

Pink-fleshed.  —  A  prolific  variety  imported  from  Cuba. 
Flesh  deep  pink,  coarse,  and  of  poor  quality.  Seeds  many  ; 
tree  very  large  and  ornamental. 


78 


Citrus  Fruits 


MANDARINS 

The  Mandarin  oranges  grown  commercially  in  California 
are  practically  all  of  one  variety,  the  Dancy,  commonly 
known  as  the  tangerine.  On  account  of  the  confusion  in 
name,  it  may  be  well  to  emphasize  the  fact  that  "  tan- 
gerine" is  the  trade  name  for  one  variety  of  Mandarin 
orange,  the  proper  name  for  which  is  Dancy.     The  Satsuma 


Fig.  21.  —  Dancy  Mandarin  orange. 


is  not  grown  commercially  in  California  and  is  represented 
only  by  occasional  specimens  in  gardens  and  nursery  collec- 
tions. Such  collections  often  contain  specimens  of  King, 
Beauty,  Mikado,  Oneco,  and  a  few  others. 

Dancy.  —  Form  oblate ;  size  medium  ;  color  very  deep 
orange  red ;  glossy ;  rind  smooth,  except  about  stem  end, 
which  is  nippled,  apex  depressed ;  segments  separating 
readily  ;  juice  abundant,  colored  ;  flavor  rich  and  sprightly  ; 
seeds  five  to  ten  or  more,  small ;  season  January  to  February. 
Tree  of  upright  growth,  fruit  borne  largely  on  the  extremities 


Varieties  79 

of  the  branches  ;  somewhat  thorny.  Parent  tree  raised  from 
seed  by  Col.  George  L.  Dancy  at  Buena  Vista,  Florida.  In- 
troduced into  cultivation  about  1872. 

Sai.suma  (Unshiu).  —  Size  small  to  medium,  2  to  3  inches 
in  diameter ;  shape  flat,  a  little  pointed  next  the  stem ; 
color  bright  orange ;  skin  rough,  wrinkled  next  the  stem, 
very  loose  and  easily  separated  from  the  flesh  ;  core,  almost 
none,  represented  by  a  cavity  often  three-eighths  inch  in  di- 
ameter in  center  ;  seeds  none  ;  flesh  orange  color,  darker  than 
the  skin,  not  so  juicy  as  some ;  flavor  very  sweet,  rich, 
very  aromatic,  peculiar  ;   quality  very  good  ;  season  early. 

This  variety  is  thornless  and  a  dwarf  grower.  It  will 
endure  more  cold  than  any  other  variety  of  edible  citrus 
fruit  except  perhaps  some  of  the  hybrids  mentioned  below. 
Should  be  worked  on  Citrus  trifoliata  stock  or  sourstock. 
Introduced  from  Japan  about  1876. 


MISCELLANEOUS    VARIETIES 

Swingle-Webber  Hybrids.  —  In  1892,  W.  T.  Swingle  and 
H.  J.  Webber  of  the  U.  S.  Department  of  Agriculture  under- 
took to  produce  new  and  improved  varieties  of  citrus  fruits 
by  hybridization  on  an  extensive  scale.  Several  new  types 
have  been  produced,  examples  of  which  are  Citranges  and 
Tangelos.  The  citranges  are  crosses  between  the  common 
sweet  orange  and  the  trifoliate  orange.  The  Rusk,  Willits, 
Norton,  Colman,  Savage,  and  Rustic  have  been  described. 
The  fruits  of  these  hybrids  are  intermediate  in  character 
between  their  parents.  They  are  not  nearly  so  good  as  sweet 
oranges,  but  they  may  be  used  for  making  soft  drinks,  pies, 
and  marmalades.  Their  special  advantage  lies  in  their  re- 
sistance to  cold,  which  enal)les  them  to  grow  a  hundred  miles 
or  more  beyond  the  northern  limit  of  the  sweet  oranges. 


80 


Citrus  Fruits 


In  California  they  are  as  yet  grown  only  as  specimens  for 
exhibition  purposes. 

The  Thornton  is  a  loose  skinned  tangelo  which  resulted 
from  crossing  the  pomelo  and  tangerine.  The  juice  is  sweet, 
lacking  the  hitter  of  the  pomelo.  The  Sampson  tangelo  is 
the  result  of  crossing  the  pomelo  with  pollen  of  Dancy. 
The  skin  is  loose  like  the  tangerine,  but  the  flavor 
includes  some  of  the  bitter  of  the  pomelo.  The  Weshart  and 
Trimble  are  crosses  between  the  Dancy  and  Parson  Brown. 


Fig.  22.  —  Satsunm  Mandarin  orange. 


The  fruits  are  larger  than  the  Dancy,  which  they  resemble 
otherwise. 

Several  thousand  hybrid  seedlings  of  several  generations 
are  now  being  grown  by  the  Department  of  Agriculture 
and  additional  varieties  of  merit  may  come  to  light  in  the 
future. 

Citron.  —  Citron  is  not  grown  commercially  to  any 
extent  in  California,  although  good  specimens  of  the  plant 
may  be  found  in  many  parts  of  the  state  and  there  is  at  least 
one  good-sized  orchard.     The  tree  is  small  in  stature  with  a 


Varieties  81 

shrub-like  growth.  It  is  more  tender  to  frost  than  the 
orange,  but  less  tender  than  the  lime.  As  early  as  1880, 
experiments  showed  that  California-grown  citron,  when 
properly  processed  or  candied,  was  equal  in  every  respect 
to  the  imported  article.  The  consumption  of  candied 
citron  in  the  United  States  is  very  small  compared  with 
that  of  oranges  and  lemons,  and  this  probably  is  the  main 
reason  why  so  little  interest  has  been  taken  in  it.  There 
appears  to  be  no  good  reason  why  California  should  not 
produce  all  the  candied  citron  consumed  in  this  country. 
Most  of  the  varieties  of  Europe  have  been  introduced  for 
trial.     The  Corsica  appears  to  be  one  of  the  best. 

Shaddock.  —  The  shaddocks  are  of  no  commercial  im- 
portance. Occasional  trees  may  be  found  in  collections  and 
in  yards  and  gardens  throughout  the  citrus  belt.  They 
appear  to  vary  in  resistance  to  cold,  some  being  as  hardy 
as  the  orange.  The  fruit  is  very  large,  round,  oblate  or  pear 
shaped  ;  skin  very  thick,  sometimes  two  inches  thick ;  seeds 
many  or  none ;  flesh  pale  yellow  or  reddish,  juice  acid  and 
often  very  bitter  ;  in  some  forms  the  young  growth  is  pubes- 
cent. Trees  ornamental,  but  not  more  so  than  the  pomelo, 
which  is  both  useful  and  ornamental. 

Lime.  —  Three  kinds  of  limes  are  grown  for  home  use  to  a 
limited  extent  in  California.  The  Sour  or  West  India  lime, 
together  with  the  Rangpur,  are  used  for  cooling  drinks 
while  the  Sweet  lime  is  eaten  out  of  the  hand  like  the 
orange.  Limes  have  never  been  grown  commercially  in 
California.  All  but  the  Rangpur  are  very  tender  to  frost, 
even  much  more  so  than  the  lemon.  The  Rangpur  is  said 
to  be  fully  as  hardy  as  the  lemon.  In  the  early  days  a  sour 
form  of  Mexican  lime  was  much  planted  as  a  hedge  plant 
aroimd  orange  orchards.  They  proved  too  tender  for  most 
localities  and  were  difficult  to  fumigate  and  keep  free  from 


Fig.  23.  —  Nagami  kumquat 


Varieties  83 

scale  insects.  For  these  reasons  they  liave  mostly  dis- 
appeared. 

Kumquat.  —  In  California  the  kumquats  are  used  chiefly 
as  ornamentals,  although  a  few  find  their  way  into 
the  markets  and  an  occasional  small  shipment  is  sent  out  of 
the  state.  They  are  especially  suited  to  pot  culture,  when 
budded  on  Citrus  trifoliata  root,  and  are  convenient  to  move 
about  as  desired  on  verandas  and  in  formal  gardens.  The 
fruit  is  small,  about  one  inch  in  diameter,  with  sweet  aromatic 
rind.  The  fruit  may  be  eaten  fresh  or  made  into  delicious 
preserves.  The  Marumi  kumquat  is  most  hardy  to  cold. 
It  has  round  fruit,  borne  in  great  abundance,  ripening  in 
October.  Twigs  somewhat  thorny.  The  Nagami  kumqiuit 
is  oblong,  slightly  pear  shaped ;  fruit  golden  yellow ;  rind 
smooth,  aromatic,  and  spicy.  Tree  thornless,  slightly  more 
tender  to  frost  than  Marumi. 

Swcd  lemon.  —  This  form  of  citrus  is  met  with  only  in 
collections,  as  there  is  no  market  demand  for  a  sweet  lemon. 
It  is  a  question  whether  this  should  be  grouped  with  the 
lemons  or  with  the  oranges.  The  fruit  is  like  a  lemon  in 
shape  but  the  flowers  are  white  like  those  of  the  orange. 

The  Trifoliata.  —  In  the  early  days  this  species  was  grown 
to  a  considerable  extent  in  California  as  a  hedge  plant. 
These  hedges  have  been  largely  done  away  with,  and  as  the 
plant  is  not  needed  as  an  ornament,  it  is  rapidly  becoming 
rare  in  the  state. 


CHAPTER  V 

THE  CITRUS  NURSERY 

The  day  of  the  seedling  orange  grove  is  past  in  Cali- 
fornia. Now  all  trees  for  new  plantings  are  bndded 
as  a  matter  of  course.  Many  of  the  large  planters  prefer, 
and  find  it  highly  profitable  to  grow  their  own  trees.  Yet 
the  business  of  raising  citrus  trees  for  sale  has  reached 
large  proportions.  Citrus  nursery  stock  not  only  fills 
the  home  demand,  but  is  shipped  in  large  quantities  to 
many  foreign  countries. 

THE    SEED-BED 

The  first  step  in  the  production  of  a  citrus  tree  is  the 
raising  of  the  root  or  stock  upon  which  the  desired  variety  is 
to  be  budded.  The  comparative  value  of  all  the  diflferent 
stocks  will  be  discussed  in  Chapter  X.  We  will  simply 
say  here  that  at  present  the  demand  is  about  as  follows : 
sour-stock,  85  per  cent ;  sweet-stock,  9  per  cent ;  pomelo, 
5  per  cent ;  and  all  others,  1  per  cent.  Sour-stock  seed 
comes  from  the  wild  thickets  of  Florida  and  Cuba,  and  is 
sold  in  California  for  from  $30  to  $50  a  bushel.  Between 
five  and  six  hundred  bushels  of  sour  orange  seed  was 
planted  in  California  in  the  year  ending  June  30,  1913. 
M 


The  Citrus  Xursrn/ 


85 


Fig.  24.  —  Citrus  beed-bed  uudci-  lulli 


86  Citrus  Fruits 

This  seed  may  he  secured  in  the  fall  and  kept  in  a  cool, 
dark  cellar.  It  should  not  become  excessively  dry.  Sour 
seed  runs  about  30, ()()()  seeds  to  the  bushel,  half  of  which 
should  come  up  and  produce  trees. 

Sweet  orange  seed  is  secured  from  the  various  seedling 
orchards  in  California.  It  will  not  endure  drying,  but 
must  be  handled  quickly  and  kept  moist.  The  seed 
stores  do  not  keep  sweet  seed  on  hand  in  quantity,  but  on 
receipt  of  an  order  will  send  a  man  with  a  seed  separating 
machine  to  a  cull  heap  near  some  packing-house,  secure 
the  amount  of  seed  desired,  and  forward  immediately  to 
the  purchaser  in  a  wet  condition.  Such  seed  must  be 
planted  at  once.  The  price  is  usually  from  .^18  to  $25  a 
bushel,  which  contains  about  35,000  seeds.  Pomelo  seed 
is  secured  either  locally  or  from  Cuba.  It  will  stand  dry- 
ing to  a  small  extent  only.  Rough  lemon  seed  may  be 
handled  much  like  sour  orange  seed. 

After  the  freeze  of  January,  1913,  it  was  found  by  experi- 
ment that  the  seed  in  oranges  which  had  been  frozen  was 
viable,  although  dark  in  color.  Almost  as  good  germina- 
tion was  secured  with  seed  from  frozen  as  from  sound 
oranges. 

It  is  an  established  custom  in  California  to  grow  citrus 
seedlings  under  a  lath  shelter,  although  one  large  nursery- 
man near  the  coast  has  broken  away  from  this  custom  and 
has  secured  good  results  by  planting  entirely  in  the  open. 
In  the  hot  interior  some  shelter  is  necessary,  but  the  trees 
grow  in  height  faster  and  are  ready  for  market  quicker 
if  grown  inider  shelter  anywhere.  The  shelters  are  cov- 
ered with  one-inch  laths  alternating  with  one-inch  open- 
ings, supported  by  uprights  set  at  convenient  distances. 


The  Citrus  Nursery  87 

The  lath  are  usually  nailed  to  cross  pieces  in  sections  of 
suitable  size  to  be  handled  by  two  men.  The  shelter  rests 
about  eight  feet  from  the  ground  and  the  lath  should  run 
north  and  south. 

The  soil  for  the  seed-bed  should  be  deep,  sandy  loam, 
free  from  stones  and  well-drained.  Virgin  soil  is  best, 
but  if  that  is  not  obtainable,  good,  rich  grain  land  will 
answer.  It  should  of  course  be  worked  up  into  a  fine 
state  of  tilth,  leveled,  and  slightly  firmed  with  a  light  roller. 
If  dry  seed  is  used,  it  should  be  soaked  for  twenty-four 
hours  before  planting.  If  the  bed  is  to  be  irrigated  by 
running  water  through  furrows,  the  ground  is  laid  off  in 
rows  twelve  inches  wide  with  very  shallow  furrows  about 
eight  or  ten  inches  wide.  A  broad,  shallow,  slow  stream 
of  water  is  needed  to  soak  through  such  rows.  The  seed  is 
planted  broadcast  on  these  wide  rows,  e^Try  sixth  row  being 
left  vacant  for  a  walk.  In  case  the  bed  is  watered  from 
above  by  automatic  sprinklers,  as  is  usually  the  case, 
the  seed  is  broadcasted  over  the  entire  surface  of  the 
ground  except  for  a  twelve-inch  path  every  ten  feet.  In 
some  cases  the  seed  is  simply  planted  about  one  inch  deep 
in  the  loose  soil  and  then  thoroughly  watered.  In  most 
cases,  however,  the  seed  is  gently  pressed  into  the  soil 
with  a  board  and  covered  from  ^  to  1  inch  deep  with 
clean  coarse  river  sand  especially  provided  for  the  purpose. 
This  covering  of  sand  prevents  the  ground  from  baking 
and  also  keeps  the  surface  dry.  The  seeds  are  placed 
about  one  inch  apart  each  way  and  if  half  of  them  or  even 
an  average  of  thirty  to  the  square  foot  grow,  the  stand  is 
considered  satisfactory . 

One  of  the  greatest  dangers  to  the  seed-bed  is  the  pos- 


88  Citrus  Fruits 

sibility  of  infestation  by  the  "damp-off"  fungi.  This 
disease  works  very  rapidly,  coverina;  a  large  area  in  a  single 
night  and  killing  the  seedlings  just  after  they  come  up. 
This  trouble  may  usually  be  prevented  by  keeping  the 
surface  of  the  ground  as  dry  as  the  requirements  of  the 
seedlings  will  permit.  The  covering  of  sand  allows  the 
water  to  pass  through  to  the  roots  while  the  surface  dries 
again  very  quickly.  The  usual  time  of  planting  is  April, 
and  most  of  the  plants  should  be  large  enough  to  sell 
one  year  after  planting. 

After  the  seedlings  are  two  months  old  they  may  be 
watered  more  generously  every  two  or  three  weeks  as 
necessary.  All  weeds  should  be  kept  out  of  the  beds,  and 
a  sharp  watch  must  be  kept  for  gophers,  moles,  and  ants. 
The  plants  are  sold  for  from  $20  to  $50  a  thousand  when 
they  are  about  a  foot  high.  The  beds  are  usually  gone 
over  twice,  the  smaller  plants  remaining  for  two  years. 
It  is  hardly  necessary  to  point  out  that  the  plants  first 
pulled  from  the  bed  are  much  more  desirable  than  those 
which  require  two  years  to  reach  marketable  size.  In 
ordering  seed-bed  stock  "first  pull"  plants  should  always 
be  specified. 

Xo  manure  or  compost  of  any  kind  should  be  used  in  the 
seed-beds  for  fear  of  encouraging  the  "damp-off"  fungi, 
which  are  usually  more  serious  in  proportion  to  the  amount 
of  freshly  decaying  organic  matter  in  the  soil.  A  moderate 
dressing  of  commercial  fertilizer  high  in  nitrogen  will 
accelerate  the  growth  of  the  plants.  Often  no  fertilizer 
is  used. 

After  the  seedlings  have  safely  passed  the  stage  when 
they  are  liable  to  damp-off,  they  may  become  infected 


The  Citrus  Nursery 


89 


with  brown-rot  guin-disease.  In  such  cases  they  \\ill 
exude  gum  just  above  the  ground  and  may  be  girdled 
and  killed.  Where  there  is  any  large  amount  of  such 
gumming,  a  thorough  spraying  with  bordeaux-mixture 
is  recommended.  Sour-stock  is  very  resistant  to  gum- 
disease  in  the  orchard,  but  this  is  not  always  the  case  in 
the  seed-bed. 

WTien  seed-bed  stock  is  to  be  dug,  the  soil  is  first  thor- 


FiG.  25.  —  Citrus  seed-bed  in  the  open. 


oughly  wet,  the  roots  slightly  loosened  with  a  long  tined 
spading-fork,  and  the  plants  drawn  by  hand.  A  varying 
proportion  of  the  plants  will  have  a  crooked  or  Z-shaped 
tap-root  known  as  "  bench-root."  When  the  seed-coat  is 
tough,  the  root  has  difficulty  in  piercing  it  and  often  makes 
several  turns  before  getting  out.  This  may  be  partly  pre- 
vented by  soaking  the  seed  over-night  before  planting. 
All  such  plants  are  inferior  and  should  be  discarded.      All 


00 


Citrus  Fruits 


Fig.  2G.  —  Bench-rooted  orange 
seedling. 


plants  which  have  gum-dis- 
ease should  also  be  thrown 
away.  After  grading,  the 
plants  are  tied  in  bunches  and 
their  tops  chopped  oft"  squarely 
with  a  hatchet  about  eight 
inchesabove  the  crowns.  They 
are  then  packed  tightly  in 
boxesorbagswith  the  tops  ex- 
posed and  with  moist  sphag- 
num moss  about  the  roots. 

Citrus  seed-beds  are  likely 
to  become  infested  with  scale- 
insects  or  other  pests,  espe- 
cially if  situated  near  infested 
orchards.  In  many  counties, 
horticultural  inspectors  have 
strict  regulations  in  regard 
to  the  admission  of  nursery- 
stock  shipped  from  other 
counties.  Such  local  regu- 
lations are  by  no  means  uni- 
form for  the  whole  state.  It 
is  wise  to  confer  with  the  ap- 
propriate officer  in  each  case 
before  the  plants  are  dug  in 
order  to  learn  just  what  kind 
of  treatment  will  be  required. 
Usually  the  plants  are  dipped, 
all  but  the  roots,  in  the  fol- 
lowing solution  : 


The  Citrus  Nursery  91 

Resin 20  1b. 

Caustic  Soda       8  lb. 

Fish  Oil 3  pt. 

Water 100  gal. 


PLANTING    SEED-BED    STOCK 

For  the  planting  of  seed-bed  stock,  a  deep  rich  loam, 
free  from  stones,  should  be  selected.  It  should  contain 
just  enough  clay  to  stick  together  well  when  the  trees  are 
balled.  The  site  for  the  planting  should  be  as  free  from 
frost  as  possible,  as  newly  set  buds  are  very  susceptible  to 
cold.  The  stock  is  planted  eighteen  inches  apart  in  rows 
three  and  a  half  or  four  feet  apart.  Especial  emphasis 
is  here  laid  upon  the  fact  that  the  roots  of  citrus  plants  are 
very  susceptible  to  injury  from  drying,  and  if  a  plant  is 
left  in  the  sun,  with  its  roots  exposed,  for  more  than  a  few 
moments,  it  is  almost  sure  to  fail  to  grow.  The  best  plan 
is  to  take  all  the  plants  into  the  field  in  the  boxes  of 
sphagnum  covered  with  wet  sacks.  Only  a  few  should 
be  handled  at  a  time  and  in  such  a  way  as  not  to  expose 
the  roots  at  all.  The  plants  are  usually  set  with  a  dibble 
or  spade,  great  care  being  taken  to  get  the  roots  in  straight 
and  not  to  set  the  plants  deeper  than  they  grew  in  the  seed- 
bed. In  planting  citrus  trees  of  any  size  or  kind,  it  is  a 
safe  rule  not  to  vary  the  depth  of  planting.  The  soil 
around  the  plants  should  be  well  firmed  to  bring  the  roots 
in  close  contact  with  moist  earth.  Irrigation  water 
should  follow  the  planters  down  each  row  as  the  work 
proceeds.  After  the  soil  is  well  irrigated  the  plantation 
should  be  gone  over  and  those  plants  which  on  account  of 
their  small  size  did  not  have  a  part  of  the  top  trimmed  off 


92  Citrus  Fruits 

at  the  seed-bed  should  be  cut  back  about  fifty  per  cent. 
These  small  plants  which  escaped  the  trimmer's  hatchet 
are  almost  sure  to  die  unless  headed  back  in  the  same 
proportion  as  the  others. 

Budding  stock  handled  as  described,  and  j^roperly  culti- 
vated and  irrigated,  should  be  large  enough  to  bud  at  the 
end  of  one  or  two  years,  usuall\'  eighteen  months.  An 
application  of  about  one-half  ton  per  acre  of  special  nursery 
stock  commercial  fertilizer  will  save  time  in  growing  the 
plants  to  budding  size.  Every  effort  should  be  made  to 
encourage  a  vigorous  growth.  It  is  false  economy  to 
bud  seedlings  which  are  too  small ;  the  ideal  size  being 
from  I  to  I'g  inch  in  diameter  three  inches  from  the 
ground. 

PROPAGATION 

Many  writers  make  the  statement  that  citrus  trees  are 
propagated  by  budding,  grafting,  cuttage,  and  layerage. 
This  is  somewhat  misleading,  inasmuch  as  budding  is  the 
universal  method  employed  in  America.  Lemon  cuttings 
may  be  made  to  root,  but  orange  cuttings  are  so  difficult 
as  to  be  out  of  the  question  entirely.  The  few  lemon  trees 
that  have  been  grown  from  cuttings  have  been  inferior 
and  have  mostly  passed  out  of  existence.  Layering 
is  never  used  and  grafting  is  very  rarely  resorted  to  except 
in  the  case  of  old  trees  which  have  been  frozen  to  the 
ground.  INIost  old  trees  which  are  top-worked  are  budded. 
The  writer  has  seen  buds  successfully  placed  directly  into 
orange  trunks  which  were  a  foot  and  a  half  in  diameter, 
although  such  a  practice  is  rare  and  not  to  be  recom- 
mended. 


The  Citrus  Nursery 


Cutting  Bud-wood 

The  success  of  the 
citrus  orchard  depends 
to  a  very  large  extent 
upon  the  care  used  in 
cutting  the  bud-wood. 
This  is  due  to  the  fact 
that  a  certain  propor- 
tion of  the  trees  in 
many  orchards  belong 
to  undesirable  types. 
This  particular  phase 
of  the  subject  will  be 
reserved  for  a  more 
extended  discussion  in 
Chapter  VII.  Suffice 
it  to  say  here  that  too 
much  pains  can  hardly 
be  taken  in  selecting 
the  mother  trees  from 
which  the  buds  are  to 
be  cut. 

Citrus  buds  should 
be  cut  from  round, 
plump  wood  taken  from 
the  fruiting  branches. 
It  is  usually  easy  to 
find  plenty  of  suitable 
bud-wood  on  lemon 
trees,  but  with  oranges, 


Fig.  27.  —  Orange  bud-wood. 


94  Citrus  Fnals 

and  especially  Navel  oranges,  this  is  often  difficult  for 
the  reason  that  the  best  trees  are  devoting  their  energies 
to  bearing  rather  than  to  growing  plump  bud-sticks.  The 
small  angular  fruiting  twigs  are  not  large  enough  to  use  to 
advantage.  On  this  account  it  becomes  necessary  to  give 
Navel  mother  trees  a  preparatory  pruning  a  year  before  the 
buds  are  wanted.  The  trees  are  thinned  out  and  cut  back 
uniformly  in  all  parts  in  order  that  there  may  be  a  more 
vigorous  growth  of  fruiting  wood.  This  pruning  should 
not  be  carried  too  far  or  water-sprouts  may  result.  Bud- 
sticks  about  a  foot  long  and  the  size  of  a  lead  pencil  made 
up  of  one-  and  two-year-old  wood  is  best.  Current  growth 
is  too  tender  and  three-year-old  wood  contains  many  blind 
buds  or  buds  which  will  be  very  slow  to  start.  Uniformity 
in  starting  the  buds  is  much  to  be  desired,  and  the  more 
care  is  used  in  collecting  buds  of  the  same  degree  of  matu- 
rity, the  more  uniform  the  nursery  will  be.  The  leaves 
are  cut  off,  leaving  a  short  stub  for  a  handle.  The  cutting 
may  be  done  in  mid-winter  and  the  accumulated  wood 
buried  in  slightly  moistened  sand  for  two  or  three  months. 
The  wood  will  cure  and  callous  on  the  lower  end,  and  cured 
wood  is  supposed  to  give  more  uniform  results.  ]Most 
budders  prefer  to  keep  the  bud-wood  in  boxes  of  moist 
sphagnum  because  the  sand  will  dull  the  budding  knives 
unless  the  wood  is  carefully  washed.  It  is  not  necessary 
to  cure  the  buds,  but  it  is  often  more  convenient  to  cut 
the  buds  all  at  one  time  and  keep  them  until  used.  It  is 
best  to  select  bud-wood  as  free  from  thorns  as  possible  for 
the  reasons  given  in  Chapter  III. 

A  great  deal  of  argument  has  been  indulged  in  over  the 
question  of  whether  buds  from  sucker  growths  or  water- 


The  Citrus  Nursery  95 

sprouts  are  as  desirable  as  buds  from  the  fruiting  brush. 
It  is  unwise  to  use  buds  from  rank  growing  water-sprouts 
because  an  excess  of  food  is  one  of  the  chief  causes  of 
variation ;  and  as  these  buds  ha\e  a  great  excess  of  food, 
they  are  somewhat  more  hkely  to  grow  into  sporting  trees 
than  are  buds  from  fruit  w  ood.  This  does  not  mean,  how- 
ever, that  good  trees  have  not  been  grown  and  may  not 
again  be  grown  from  sucker  buds.  We  simply  take  the 
position  that  it  is  an  unwise  policy  for  the  reason  given. 

Time  of  Budding 

Citrus  stock  may  be  budded  at  any  time  of  the  year  or 
whenever  the  bark  will  slip,  but  the  best  time  is  during 
the  months  of  October  and  November,  in  which  case  the 
buds  usually  remain  dormant  until  spring.  Stocks  upon 
w^hich  the  buds  fail,  may  be  rebudded  in  April  or  May.  It 
often  happens,  unfortunately,  that  a  certain  proportion 
of  fall  set  buds  start  into  growth  immediately,  thus  ex- 
posing a  few  inches  of  very  tender  growth  to  the  dangers 
of  winter.  In  such  a  case,  the  number  of  orchard  heaters 
set  in  the  nursery  should  be  increased  and  the  fires  started 
at  the  first  indication  of  frost. 

Method  of  Budding 

In  California,  the  usual  method  of  insertion  is  the  shield 
or  T  method.  The  bud-stick  is  grasped  firmly  with  the 
tip  toward  the  operator.  With  a  very  sharp  budding  knife 
the  bud  is  cut  by  inserting  the  blade  about  one-half  inch 
below  and  drawing  it  beneath  the  bud  and  out  about 
one-half  inch  above,  thus  cutting  a  bud  about  one  inch 


96 


Citrus  Fruits 


loiifi;.  The  bud  is  held  firinl\-  ])etween  the  thumb  and 
the  knife  l)hide  while  a  slit  is  eut  in  the  bark  of  the  stock 
about  three  inches  above  the  ground  and  one-half  inch 
long.  At  the  top  of  this  slit,  a  cross  cut  is  made  with  the 
edge  of  the  blade  of  the  knife  inclined  downward.  The 
bud  is  then  inserted  in  this  slit,  being  careful  to  have 
the  leafscar  or  bottom  of  the  bud  down.     The  back  of 

the  point  of  the  knife 
is  then  placed  on  the 
leafscar  and  the  bud 
pushed  down  until 
the  upper  end  is  be- 
low the  cross  cut, 
and  in  any  event  un- 
til the  pressure  of  the 
bud  begins  to  split 
the  bark  beyond  the 
previously  made 
slit.  A  strip  of  waxed 
cloth  is  then  wrapped 
c[uite  firmly  around 
the  stock  five  or  six 
times  so  as  to  cover 
the  bud  completely. 
Some  budders  prefer  to  leave  the  eye  exposed  but  this  is 
not  necessary.  Buds  are  usually  set  on  any  side  as  re- 
gards the  points  of  the  compass,  or  in  other  words,  the  side 
most  convenient  to  the  budder.  The  bark  usually  slips, 
and  the  buds  take  better,  directly  under  a  small  branch. 
Some  budders  prefer  to  use  the  inverted  T  method. 
The  cross  cut  in  the  bark  of  the  stock  is  made  lower  and 


Cutting  a 


The  Citrus  Nursery 


97 


the  bud  pushed  upward  instead  of  downward  into  place. 
The  inverted  T  is  somewhat  better  for  fall  budding,  as  the 
cross  cut  or  obstruction  when  placed  below  the  bud  tends 
to  produce  a  quiescent  state  which  is  desired  during 
winter.  The  cross  cut  when  placed  above  the  bud  tends 
to  produce  a  strong  lateral  growth  and  is  therefore  best 
for  spring  budding. 

Most  seedlings 
tend  to  branch  close 
to  the  ground  and  as 
a  result  buds  are 
often  placed  quite 
close  to  the  ground. 
This  is  a  mistake  in 
most  cases,  especially 
when  using  sour 
orange  as  a  stock. 
This  stock  owes  its 
popularity  largely  to 
its  resistance  to  gum- 
disease,  but  when 
buds  are  placed  low 
this  resistance  is 
much  reduced.  The  object  should  be  to  keep  the 
wood  of  the  scion  as  far  from  the  ground  as  practic- 
able in  order  to  avoid  gum-disease  infection,  which 
comes  from  the  soil.  If,  on  the  other  hand,  buds  are 
placed  too  high,  a  crooked  and  ugly  trunk  will  result. 
While  high  budded  trees  are  less  comely  and  do  not  sell 
as  well  on  account  of  the  crook  in  the  trunk,  still  they  are 
the  more  to  be  desired,  especially  when  intended  to  be 


Fig.  29.  —  Making  incision  in  stock. 


98 


Citru.s-  Fntitf 


planted  on  heavy  soils  or  near  the  eoast,  where  gnni-dis- 
ease  is  prevalent. 

After  about  ten  days,  the  buds  should  be  unwrapped  and 
examined.  If  they  have  taken,  as  evidenced  by  a  grayish 
line  of  callous  tissue  forming  around  the  edges,  the  wrap- 
pings are  loosened,  to  be  removed  entirely  after  about 
thirty  days  in  the  case  of  the  fall  buds  and  twenty  days 

in  the  case  of  spring 
buds,  or  whenever 
the  bud  is  w'ell 
healed. 

In  the  case  of  fall 
buds  which  have  re- 
mained dormant,  as 
they  should  during 
winter,  the  tops  of 
the  stock  are  cut 
back  in  the  spring  to 
within  six  inches  of 
the  buds  in  order  to 
increase  the  sap  pres- 
sure and  force  them 
into  a  more  uni- 
form growth.  The 
promptness  with  which  a  bud  starts  depends  to  some 
extent  on  its  age  and  position  on  the  bud-stick.  Uni- 
formity of  growth  is  greatly  to  be  desired  in  the 
nursery,  and  such  cutting  back  tends  to  force  all  the 
buds  to  start  more  nearly  at  the  same  time.  The  six 
inches  or  more  of  stock  which  is  left  affords  a  certain  pro- 
tection to  the  young  shoot  and  reduces  the  possibility 


Fig.  30.  —  Inserting  bud. 


Citrus  Nursery 


99 


of  the  bud  being  involved  in  any  dying  back  which  may 
occur.  After  the  young  shoot  has  grown  eight  or  ten 
inches  the  stub  of  the  stock  is  sawed  off  smoothly,  the 
edges  trimmed  with  a  sharp  knife,  and  the  cut  surface 
covered  with  liquid  grafting  wax. 

In  the  case  of  spring  set  buds,  the  same  custom  prevails 
except  that  some- 
times the  stocks  are 
only  partially  cut 
back  at  first.  With 
late  set  buds  there 
is  sometimes  a  dan- 
ger of  the  superabun- 
dance of  sap  during 
hot  weather  "drown- 
ing out"  the  buds  if 
all  the  top  of  the 
stock  is  removed  too 
suddenly.  Occasion- 
ally the  tops  are 
"lopped"  or  cut  half 
through  and  bent 
down  in  the  middles, 

in  order  to  gradually  change  the  flow  of  the  sap. 
are  removed  entirely  after  a  month  or  six  weeks. 

Citrus  budding  is  often  done  l)y  expert  budders  by  con- 
tract at  about  $10  a  thousand,  the  budder  guaranteeing 
a  95  per  cent  stand  and  furnishing  his  own  buds,  wrapi)ing 
cloth,  and  the  like.  Eight  and  a  half  dollars  a  thousand 
is  a  common  price  when  buds  are  furnished.  This  of 
course  applies  to  regular  fall  budding. 


Tj-ing  inserted  hud. 


They 


100  Citrus  Fruits 

Traiuiug  the  Young  Tree 

In  order  to  insure  a  perfectly  straight  trunk  the  young 
trees  are  trained  to  stakes.  The  .stakes  may  be  set  soon 
after  the  buds  have  started  growth.  The  stakes  used  in 
Cahfornia  are  ordinary  building  laths.  They  are  driven 
into  the  ground  close  l>y  the  stock  on  the  side  next  the 
scion.  As  the  young  shoot  grows  it  is  tied  to  the  stake 
with  soft  raffia.  A  tie  is  made  every  three  inches,  the 
raffia  being  drawn  up  snugly  under  a  leaf.  The  rough 
unfinished  surface  of  the  lath  is  an  advantage,  as  it  pre- 
vents the  raffia  from  slipping  down.  Careful  attention 
to  tying  is  necessary  in, order  to  secure  straight  trunks. 
While  going  over  the  trees  for  tying  it  is  also  necessary 
to  remove  any  side  branches  which  may  put  out,  as  well 
as  the  numerous  suckers  which  arise  from  below  the  bud. 
These  sprouts  should  be  rubbed  off  with  the  thumb  while 
still  very  young,  and  this  necessitates  going  over  the  trees 
every  three  or  four  weeks  during  the  first  summer. 

Nursery  trees  should  be  allowed  to  grow  three  feet  tall 
and  then  headed  back  to  27  or  30  inches.  This  will  insure 
the  main  branches  being  set  upon  stronger  wood  than  if 
the  terminal  bud  was  pinched  as  soon  as  it  reached  the 
desired  height.  Branches  which  are  to  be  the  framewc^rk 
of  the  future  tree  are  encouraged  to  put  out  on  all  sides 
and  distributed  over  the  upper  twelve  inches.  From 
three  to  six  main  branches  are  sufficient.  The  old  custom 
was  to  allow  the  framework  branches  to  arise  from 
near  the  same  point.  Experience  has  shown  that  such 
branches  split  down  badly  and  require  much  bolting  when 
the  trees  grow  old.     This  is  being  abandoned,  especially 


The  Citrjis  Nursery 


101 


with  lemon  trees,  in  favor  of  the  less  comely  but  more  de- 
sirable distribution  of  main  branches. 


Fic.  32.  —  Orange  buds  in  nursery  row  tied  to  lath  stakes. 

Often  a  tree  will  make  several  growths  before  it  reaches 
the  top  of  the  stake.  The  end  of  each  growth  is  marked 
by  a  ring  or  node  of  thickened  tissue.     There  is  a  wide- 


102  .     Citrus  Fruits 

spread  belief  that  a  tree  with  several  of  these  nodes  on  the 
trunk  is  to  be  preferred  to  one  which  made  one  growth  to 
the  top  of  the  stake.  'J'he  reason  assigned  is  that  it  indi- 
cates slow  growing  and  heavy  fruiting  qualities.  It  is 
doubtful  whether  there  is  sufficient  basis  in  fact  for  this 
belief,  although  there  are  some  arguments  in  its  favor.  It 
is  not  unlikely  that  in  the  case  of  the  Washington  Navel 
orange  there  may  be  some  correlation  between  the  num- 
ber of  nodes  and  fruitfulness,  but  this  is  probably  not  the 
case  with  lemons. 

The  citrus  nursery  should  be  thoroughly  cultivated  and 
irrigated  and  the  trees  kept  in  vigorous  growth.  Com- 
mercial fertilizer  should  be  applied  liberally,  usually  a 
ton  to  a  ton  and  a  half  to  the  acre  of  a  complete  fertilizer 
high  in  nitrogen.  One  or  two  years  are  required  to  grow 
a  marketable  tree.  We  find,  therefore,  that  a  total  of  from 
four  to  six  years  is  required  from  planting  the  seed  to  set- 
ting the  trees  in  orchard  form. 

Trees  are  graded  and  priced  according  to  caliper  measure- 
ment one  inch  above  the  bud.  Well-grown  one-year  trees 
are  often  acceptable,  but  usually  two-year  trees  are  much 
better.  Prices  in  California  vary  from  fifty  cents  to  one 
dollar  and  a  quarter  a  tree. 

PREPARING    TREES    FOR   SHIPMENT 

Citrus  trees  may  be  dug  with  naked  roots,  cut  back  to 
the  trunk,  shipped  long  distances,  and  planted  with  perfect 
success ;  but  on  account  of  the  fact  that  it  is  difficult  to 
always  see  that  the  tender  roots  are  not  exposed,  there  is 
much  loss   from  the    carelessness  of    laborers,    and  the 


The  Citrus  Xurscri/ 


103 


custom  of  balling  trees  has  become  general  in  California. 
Balled  trees  are  much  less  perishable,  may  be  handled  with 
more  assurance,  do  not  require  all  the  top  to  be  removed, 
do  not  need  to  be  reheaded,  and  make  a  somewhat  better 
showing  the  first  year.     On  the  other  hand,  the  cost  of 


1 

1 

Fig.  33.  —  Healing  of  the  bud  union. 

balling  is  great  and  the  freight  on  thirty  to  forty  pounds 
of  earth  with  each  tree  adds  considerably  to  the  cost. 

It  is  recommended,  therefore,  that  trees  be  balled  where 
the  distance  to  be  transported  is  short  or  when  inexperi- 
enced men  are  to  do  the  planting.  Where  the  owner  is 
able  to  look  after  the  planting  personally  the  trees  may  be 
dug  with  naked  roots  and  a  considerable  saving  on  freight 
and  expense  of  balling  will  result.  Where  trees  are  to  be 
moved  only  a  short  distance,  as  from  one  part  of  a  ranch 


104 


Citrus  Fruits 


to  another,  the  following  method  is  sometimes  used. 
Short  sections  of  ten-inch  pipe  are  placed  over  the  trees 
and  driven  into  the  ground,  thus  cutting  all  roots  but 
the  tap-root,  which  is  cut  with  a  spade.      The  trees  are 


Fig.  M.  —  Hailing  orange  trees  in  the  nursery. 


then  moved  and  the  core  of  earth  containing  the  trees  is 
slipped  out  of  the  pipe  into  the  hole  prepared,  the  pipes 
being  used  again  and  again. 

When  trees  are  to  be  balled,  a  trench  a  foot  wide  and 
fifteen  inches  deep  is  dug  alongside  of  a  row  of  trees  and 
with  careful  work  the  tap-root  may  be  cut  and  the  tree 


The  Citrus  Nursery  105 

lifted  with  a  ball  of  earth.  This  is  carefully  wrapped  in 
old  sacking  and  firmly  tied  with  strong  cord.  The  top  is 
cut  back  somewhat,  the  leaves  remo\ed  from  the  trunk, 
and  the  trees  are  ready  for  shipment.  A  bailer  and  tyer 
work  together  and  in  good  soil  shoidd  turn  out  about  one 
hundred  and  se\enty-five  trees  a  da>'.  Counting  the  men 
engaged  in  digging  trenches  and  defoliating,  a  crew  of 
twenty-five  men  should  dig  and  ball  about  fifty  trees  a 
day  for  each  man  in  the  crew\  When  a  few  balled  trees 
are  shipped,  they  must  be  boxed  at  considerable  expense. 
In  the  case  of  carload  lots,  they  are  simply  stacked  closely 
together  in  ordinary  box  cars,  the  balls  resting  on  a  layer 
of  moist  straw  on  the  bottom  of  the  car.  En  route  the 
balls  should  be  kept  moist,  but  not  so  w^et  as  to  start 
growth.  California  now  produces  upward  of  a  million 
and  a  quarter  citrus  trees  a  year,  many  of  which  are 
shipped  to  various  foreign  countries  including  South 
Africa,  New  Zealand,  and  India.  Foreign  shipments 
always  go  forward  with  bare  roots  firmly  packed  in 
sphagnum  moss. 


CHAPTER  VI 

HORTICULTURAL  INSPECTION  AND 
QUARANTINE 

California  has  had  much  experience  with  horticultural 
statutes.  Many  dift'erent  laws  ha^•e  been  passed  and 
amended  from  time  to  time  during  the  last  thirty  years. 
During  this  time  there  has  been  hardly  a  session  of  the 
state  legislature  which  has  not  changed  the  law  in  some 
particulars.  The  citrus  industry  is  so  vitally  concerned 
with  the  activities  of  the  State  Commission  of  Horticul- 
ture as  to  warrant  a  description  of  this  important  agency. 

In  INIarch,  1908,  the  State  Commissioner  of  Horticulture 
published  a  handbook  containing  all  the  laws  together 
with  the  court  decisions  and  legal  opinions  relating  thereto, 
corrected  to  that  date.  More  recent  laws,  together  with 
a  number  of  quarantine  orders,  may  be  found  in  the  Com- 
missioner's "Monthly  Bulletin,"  Vol.  II, pp.  337-351, 1913. 

The  ordinances  of  the  different  counties  relating  to  the 
movement  of  nursery  stock  from  one  county  to  another 
may  be  secured  from  the  respective  County  Horticultural 
Commissioners. 

THE    STATE    COMMISSIONER    OF    HORTICULTURE 

This  official  is  appointed  by  the  Governor  for  a  term  of 
four  years  or  until  his  successor  is  appointetl. 
106 


Horticultural  Inspection  and  Quarantine  107 

While  the  state  law,  approved  April  26,  1911,  directs 
the  Commissioner  to  collect  books,  pamphlets,  and  periodi- 
cals and  acquire  all  possil)le  information  by  correspondence 
for  the  furtherance  of  the  horticultural  industries,  still 
his  principal  function  is  that  of  a  police  officer.  He  is 
by  virtue  of  his  position  the  state  horticultural  quarantine 
officer,  and  as  such  is  responsible  for  the  rigid  exclusion 
from  the  state  of  injurious  insects  and  plant  diseases,  and 
the  prevention  of  any  further  dissemination  of  such  pests  as 
are  already  established  m  certain  localities  within  the  state. 

In  order  to  enforce  the  state  quarantine  law  approved 
January  2,  1912,  the  Commissioner  maintains  an  office 
with  a  force  of  inspectors  at  San  Francisco,  another  at  Los 
Angeles,  and  a  third  at  San  Diego.  These  hispectors  go 
through  the  cargoes  of  every  ship  arriving  from  any  foreign 
port  or  from  Honolulu,  and  the  baggage  of  every  passenger. 
If  any  plants,  fruits,  or  seeds  are  found  to  be  infested  with 
injurious  insects  or  diseases,  they  are  fumigated  at  the 
expense  of  the  owner,  or  treated  in  such  a  way  as  to  kill 
the  pests.  If  this  is  impracticable,  the  plants  are  destroyed 
or,  at  the  option  of  the  owner,  returned  whence  they  came. 
In  some  cases  the  State  Commissioner  may,  with  the 
written  approval  of  the  Governor,  issue  a  quarantine  order 
against  certain  fruits  or  plants  from  certain  countries. 
Such  articles  are  then  considered  contraband  and,  if  an 
attempt  is  made  to  introduce  them,  are  confiscated  and 
destroyed  by  the  inspectors  regardless  of  whether  they  are 
infested  or  not. 

The  State  Commissioner  may  appoint  the  County  Horti- 
cultural Commissioners  or  their  agents  special  quarantine 
officers  for  the  purpose  of  inspecting  shipments  coming 


108 


Citrus  Fruits 


from  the  Eastern  states  or  Europe  and  hilled  to  interior 
points  in  California.  The  common  carriers  are  by  law 
forbidden  to  deliver  to  a  consignee  within  the  state  any 
shipment  of  horticultural  goods  until  such  shipment  has 
been  inspected,  declared  free  from  pests,  and  formally 
released  in  writing  by  a  duly  appointed  horticultural  in- 


'^ 

.flUiiMidMl 

f     iiW 

^■"^W^»"^*i^"i^*l**4                                        lllliH 

^ 

^^^^l^g^^J^ 

Fig.  35.  —  A  -shipment  of  defoliated  balled  orange  trees. 


spector.  The  inspector  may  exercise  his  discretion  in  re- 
gard to  the  disposition  of  infested  shipments.  He  may  rid 
the  plants  of  pests  by  fumigation  or  other  means  and  then 
release  them  upon  payment  of  the  costs  ;  or  if  in  his  judg- 
ment the  infestation  is  severe  or  the  pest  particularly  dan- 
gerous, he  may  destroy  the  goods  or  cause  their  reshipment 
out  of  the  state. 

As  an  example  of  a  quarantine  order  now  in  force  we  may 


Horticnltiiral  Inspection  and  Quarantine  109 

cite  Order  No.  21,  which  forbids  the  shipment  of  any  of  the 
forty  listed  host  plants  of  the  citrus  white  fly,  Aleyrodes 
citri  and  Aleyrodes  nuhifera,  from  North  Carolina,  South 
CaroHna,  Georgia,  Florida,  Alabama,  Mississippi,  Loui- 
siana, and  Texas  into  the  state  of  California.  This  order 
prevents  California  growers  from  securing  nursery  stock 
or  scions  of  new  varieties  in  any  of  the  above  mentioned 
states.  By  special  arrangement,  hoAvever,  the  citrus  seeds 
planted  by  nurserymen  which  come  from  Florida  and  Cuba 
are  admitted,  provided  they  are  sent  in  care  of  some  desig- 
nated agent  of  the  Commission,  who  fumigates  them  be- 
fore delivery  to  consignee. 

Another  quarantine  order  prevents  the  importation  from 
Hawaii  of  mangoes,  oranges,  avocados,  and  other  fruits 
which  are  hosts  of  the  Mediterranean. fruit  fly,  Ceratitis 
capitata.  Still  another  order  forbids  the  shipment  into 
California  from  Mexico  of  oranges,  mangoes,  or  other  fruits 
which  are  hosts  of  the  Mexican  orange  maggot,  Tripeta 
ludens.  These  latter,  however,  have  now  been  superseded 
by  national  quarantine  orders. 

It  has  long  been  the  custom  of  the  State  Commissioner 
of  Horticulture  to  hold  two  meetings  each  year  which  are 
known  as  State  Fruit  Growers'  conventions.  One  meeting 
is  usually  held  at  some  convenient  place  in  the  northern 
part  of  the  state  and  the  other  in  the  southern  part.  The 
proceedings  of  these  conventions  are  brought  together, 
edited,  publishetl,  and  distributed  free  by  the  State  Com- 
missioner. The  meethig  hekl  at  Davis  in  June,  1914,  was 
the  fort>-fifth  such  convention.  The  printed  proceed- 
ings of  these  conventions  represent  a  very  fertile  source  of 
information  for  the  student  of  California  citriculture. 


110  Citrus  Fruits 


THE    COUNTY    COMMISSIONERS    OF    HORTICULTURE 

The  California  State  law  providinjj:  for  County  Horti- 
cultural Commissioners  has  been  amended  many  times. 
The  present  law,  approved  March  25,  1911,  provides: 
that  whenever  a  petition,  setting]:  forth  the  legitimate  need 
for  a  Commissioner  and  signed  by  twenty-five  or  more 
resident  freeholders  who  are  possessed  of  horticultural 
properties,  is  presented  to  the  county  board  of  sujjer- 
visors,  said  supervisors  are  requirerl  to  a])point  a  County 
Horticultural  Commissioner  from  the  list  of  eligibles,  who 
must  have  passed  the  examinations  held  by  the  state 
board  of  horticultural  examiners.  The  term  of  the  County 
Commissioner  is  four  years. 

Many. of  the  duties  of  the  County  Commissioner  are  pre- 
scribed by  county  ordinances,  and  these  vary  in  the  differ- 
ent counties.  The  Commissioner  is  usually  required  to 
keep  informed  as  to  the  particular  localities  within  the 
county  where  pest  infestation  is  serious.  He  must  have 
the  orchards  and  ornamental  plantings  inspected,  and  when 
in  his  judgment  the  scale  insects  have  increased  in  any 
orchard  until  they  constitute  a  public  nuisance,  he  must 
serve  written  notice  on  the  owner  to  abate  the  nuisance 
by  fumigating,  spraying,  or  otherwise  within  a  certain  time 
limit.  If  this  order  is  not  complied  with,  the  Commis- 
sioner may  enter  the  premises  and  abate  the  nuisance,  the 
cost  of  such  work  becoming  a  lien  on  the  property.  If  the 
cost  of  the  work  is  not  paid,  enough  of  the  property  may 
be  sold  at  public  auction  to  satisfy  the  lien. 

Such  ordinances  have  been  tested  in  the  courts  and 


Horticultural  Inspection  and  Quarantine  111 

found  constitutional,  the  acts  of  the  County  Commissioners 
being  upheld  in  each  instance. 

County  Commissioners  may  appoint  k)cal  inspectors 
in  outlying  towns  and  fruit  districts  within  the  county. 
The  Commissioner  also  renders  an  annual  report  to  the 
State  Commissioner  and  a  monthly  report  to  the  board 
of  supervisors  of  his  county. 

As  special  state  quarantine  officers  it  is  the  duty  of  the 
County  Commissioners  and  their  agents  to  inspect  every 
shipment  originating  outside  of  the  state,  as  well  as  those 
coming  from  other  parts  of  the  state  which  arrive  in  their 
territory. 

It  is  also  the  duty  of  the  Commissioner  to  inspect  every 
outgoing  shipment  of  horticultural  goods  before  it  is  ac- 
cepted by  a  common  carrier.  The  law  requires  common 
carriers  to  accept  only  such  packages  or  lots  as  bear  a 
statement  signed  by  the  Commissioner  or  his  agent 
certifying  that  the  goods  are  free  from  injurious  pests. 
We  find,  therefore,  that  every  package  of  horticultural 
goods  is  inspected  twice,  once  at  the  point  of  shipment 
and  again  at  the  place  of  delivery. 


THE    NECESSITY    FOR   INSPECTION 

The  question  may  arise  in  the  mind  of  the  reader  as  to 
whether  this  complex  system  of  quarantine  and  inspection 
is  worth  while.  The  answer  to  this  question  may  be  found 
in  the  following  quotation  from  California  Experiment 
Station  Bulletin  No.  214,  by  H.  J.  Quayle. 

"  That  insect  pests  are  one  of  the  important  factors  m 
the  citrus  fruit  industry  of  California  is  shown  by  the  fact 


112 


Citrus  Fruits 


that  more  than  half  a  million  dollars  are  expended  annually 
hi  their  control.  This  amount  includes  only  what  is  actu- 
ally ex})ende(l  in  fumigation  and  spraying,  and  does  not 
take  into  consideration  tlie  loss  of  fruit  from  improperly 
treated  trees  or  trees  not  treated  at  all.     The  cost  of  fumi- 


urangf  trues  bulled,  ready  for  market. 


gation  in  one  county  alone  amounts  to  -5200,000  annually. 
P\irthermore  each  county  maintains  a  horticultural  Com- 
missioner, and  many  of  them  a  corps  of  inspectors,  pri- 
marily on  account  of  insect  enemies,  who  are  charged  with 
the  quarantine  and  inspection  work,  the  cost  of  which  in 
some  of  the  counties  may  run  as  high  as  $25,000  annually. 
All  of  this  vigilance  seems  to  be  warranted  by  thirty 


Horticultural  Inspection  and  Quarantine  113 

years'  experience  of  the  most  important  fruit  section  of  the 
United  States. 

"  It  has  been  estimated  that  the  average  cost  of  fumiga- 
tion per  tree,  taking  the  whole  of  the  citrus  belt,  amounts 
to  about  30  or  40  cents,  which  means  an  expense  of  approx- 
imately $30  to  $40  per  acre,  and  this  is  done  on  an  average 
about  every  other  year.  This  is  intensive  insect  fighting, 
but  when  the  improved  market  value  of  the  fruit  is  con- 
sidered, it  is  money  judiciously  spent  with  such  a  valuable 
crop  as  the  orange  or  lemon." 

In  conclusion  we  may  say  that  the  benefits  of  exemption 
from  scale  insects  is  clearly  reflected  in  the  prices  asked 
for  land  and  bearing  orchards  in  scale-free  localities. 
The  annual  tax  of  15  to  20  cents  a  tree  for  fumigation  is 
especially  unwelcome  and  growers  in  scale-free  localities 
do  well  to  exercise  every  possible  precaution  to  prevent 
the  introduction  and  establishment  of  such  relentless 
tax-gatherers  as  the  insect  pests  and  plant  diseases  have 
proved  themselves  to  be. 


CHAPTER   VII 

IMPROVEMENT   OF   CITRUS    TREES   BY 
BREEDING 

The  production  of  citrus  fruits  in  California  and 
Florida  is  increasing  at  a  rapid  rate.  The  shipments 
from  these  two  states  for  the  season  1913-14  reached  a 
total  of  about  sixty  thousand  cars.  Thousands  of  acres  of 
young  orchards  are  just  coming  into  bearing,  and  the  near 
future  will  undoubtedly  witness  a  large  increase  in  produc- 
tion. The  problem  of  how  to  make  a  profit  in  the  business 
in  spite  of  the  heavy  production  will  loom  large  in  the 
future. 

Undoubtedly  a  great  deal  may  be  accomplished  through 
the  marketing  organizations  by  securing  better  distribu- 
tion of  the  fruit  and  increased  consumption  through  proper 
advertising.  Yet  it  is  a  fact  that  much  loss  is  at  present 
due  to  a  lack  of  varieties  which  are  well  suited  to  the  cli- 
matic and  soil  conditions  under  which  they  are  grown, 
to  ignorance  in  regard  to  adaptation  of  varieties,  and  to 
sports  or  aberrant  forms  which  occur  throughout  the 
citrus  growing  districts  much  more  commonly  than  is 
generally  recognizetl. 

Through  carelessness  or  ignorance  in  the  selection  of 
bud-wood  many  poor  or  even  worthless  types  have  been 
114 


Improvement  of  Citrus  Trees  by  Breeding         115 

propagated  and  widely  planted.  The  poor  financial  show- 
ing made  by  many  orchards  is  due  largely  to  the  prepon- 
derance of  trees  belonging  to  aberrant  forms. 

While  some  progress  may  be  made  toward  improved 
varieties  through  hybridization,  the  waiter  is  strongly  of 
the  opinion  that  much  better  and  quicker  results  are  to  be 
secured  through  the  careful  selection  of  desirable  bud- 
sports  which  occur  rather  frequently  on  trees  of  the  old 
standard  varieties. 


HYBRIDIZATION 

The  object  of  hybridization  is  to  secure  seedlings  which 
combine  the  desirable  characteristics  of  two  or  more  parent 
trees.  The  flowers  of  the  selected  parent  trees  are  cross- 
pollinated  by  hand,  using  great  care  in  excluding  foreign 
pollen. 

Cross-pollination  is  a  very  easy  operation  and  may  be 
performed  successfully  by  any  one  willing  to  use  a  little 
care  and  perseverance.  The  structure  of  the  citrus 
flower  is  very  simple  and  a  knowledge  of  the  functions  of 
the  different  parts  is  easily  acquired  by  the  study  of  the 
diagram  at  Fig.  14.  The  essential  organs  of  the  flower 
are  the  stamens  and  pistil.  The  anthers  bear  the  pollen 
grains,  each  one  of  which  when  placed  on  the  stigma  will 
germinate  and  send  a  tube  down  through  the  style  and  into 
the  ovary.  The  male  nucleus  from  the  pollen  grain  passes 
down  through  this  tube  and  conies  in  contact  with  the 
female  egg-cell  of  the  ovule  with  which  it  fuses,  thus  bring- 
ing about  fertilization  and  the  combination  of  the  charac- 
ters of  the  two  parents.     A  separate  pollen  grain  is  needed 


116  Citrm  Fruits 

for  each  seed,  and  tlie  parental  characters  may  be  com- 
bined in  a  different  way  in  each  case.  After  the  ovaries 
have  been  fertilized  they  grow  into  viable  seeds.  It  is 
not  always  necessary  for  citrus  flowers  to  be  pollinated  and 
fertilized  in  order  to  produce  fruit.  The  Navel  orange  for 
instance  rarely  contains  seeds  and  on  that  account  is 
knov,n  as  a  parthenocarpic  fruit. 

When  cross-pollination  is  accurately  performed,  it  is 
necessary  to  place  paper  bags  over  the  blossoms  which 
are  to  be  used  as  a  source  of  pollen,  before  the  buds  open. 
This  is  necessary  in  order  to  prevent  the  possibility  of  the 
mixing  of  pollen  by  insects.  The  pollen  may  be  gathered 
and  dried  on  papers  and  stored  in  small  bottles  for  use, 
but  it  is  often  convenient  to  cut  the  twigs,  bag  and  all,  and 
carry  them  to  the  tree  which  is  to  be  used  as  a  female 
parent.  Large  buds  just  ready  to  open  should  be  selected 
and  all  the  smaller  buds  and  open  flowers  on  the  twig 
removed.  The  petals  are  pried  apart  with  a  small  pair 
of  forceps  and  an  anther  bearing  ripe  pollen  is  taken 
from  a  blossom  within  one  of  the  bags  and  placed  firmly 
upon  the  stigma,  pressing  it  down  into  the  drop  of  white 
mucilage.  If  no  mucilage  appears  on  the  stigma,  it  is 
evidence  that  the  bud  is  immature.  The  camel's-hair 
brush  commonly  used  in  cross-pollinating  fruits  is  not 
satisfactory  in  citrus  work  on  account  of  the  copious 
excretion  of  mucilage  by  the  stigma.  It  is  wise  to  cross- 
pollinate  several  buds  on  each  twig,  as  many  are  apt  to 
drop  off.  After  the  pollen  has  been  placed  on  the  stigma, 
the  small  immature  anthers  must  be  removed  from  the 
flower  for  fear  that  the  pollen  produced  later  by  them  may 
interfere  with  the  results.     In  the  case  of  the  Navel  orange 


Improvement  of  Citrus  Trees  by  Breeding         117 

this  is  not  necessary,  as  the  anthers  do  not  produce 
pollen.  After  the  operation  has  been  completed  a  paper 
bag  should  be  placed  over  the  twig  and  tied  with  string. 
After  two  or  three  weeks  the  paper  bags  may  be  replaced 
by  cheesecloth  bags,  which  remain  on  till  the  fruit  is 
picked  for  seed. 

The  value  of  crosses  or  hybrids  produced  in  this  way 
cannot  be  determined  for  several  vears,  or  until  the  trees 


Fig.  37. — Type  of  standard  Washington  Navel  orange. 

have  been  reared  to  fruiting.  By  top-working  buds  taken 
from  the  young  seedlings  into  old  trees  the  fruit  may 
be  secured  earlier. 

The  improvement  of  citrus  fruits  by  this  method  is  very 
slow  and  the  results  uncertain.  Moreover  it  is  doubtful 
whether  an  entirely  new  variety  of  orange  or  lemon,  how- 
ever good,  could  gain  much  recognition  in  California  in  the 
face  of  the  popularity  of  the  Xavel  and  ^^alencia  oranges 
and  the  Eureka  lemon.  The  history  of  the  industry  in 
California  has  shown  a  constant  elimination  of  varieties 


118  Citrus  Fruits 

rather  than  the  acquisition  of  new  ones.  The  greatest 
field  for  hybridization  work  lies  with  the  pomelos.  There 
is  at  present  no  thoroughly  satisfactory  variety  of  ])omelo 
suited  to  the  climatic  and  soil  conditions  of  California. 
The  feeling  of  the  growers  in  regard  to  better  varieties  of 
oranges  and  lemons  was  clearly  shown  some  years  ago 
when  E.  J.  Wickson  sent  out  a  circular  letter  to  determine 
the  most  urgent  needs  along  the  line  of  citrus  breeding. 
The  response  of  the  growers  was  significant.  They  re- 
plied that  what  was  needed  most  was  a  Washington 
Navel  which  would  color  earlier ;  a  Navel  which  would 
hang  on  the  tree  like  a  Valencia;  a  Navel  that  would 
not  split ;  a  Navel  that  would  not  puff ;  and  a  Navel 
more  hardy  to  frost.  Some  growers  wanted  a  Valencia 
that  would  not  turn  green  a  second  time,  or  a  Valencia 
without  seeds. 

The  most  expeditious  way  of  securing  the  results  desired 
by  the  growers  is  by  selecting  and  propagating  those  sports 
from  the  varieties  mentioned  which  approach  most  closely 
the  desired  types.  Such  bud  variations  occur  quite  fre- 
quently in  citrus  trees.  They  present  a  vast  field  for  the 
work  of  improvement  of  types. 

VEGETATIVE    MUTATIONS    OR   BUD-SPORTS 

Citrus  trees,  in  common  with  other  plants,  are  observed 
to  vary  in  several  ways.  There  are  fluctuations  or  un- 
stable differences  which  come  and  go  in  response  to  the 
various  complex  stimuli  produced  by  changing  conditions 
of  soil  and  climate,  or,  in  other  words,  changes  of  food  and 
environment.     There  are  also  sudden  changes  known  as 


Improvement  of  Citrus   Trees  by  Breeding 


119 


mutations  which  result  in  new  forms  that  are  stable  and 
form  the  starting  point  of  new  strains  or  varieties. 

Fluctuations  are  of  two  kinds,  regular  and  fortuitous. 
As  an  example  of  regular  fluctuation  we  may  cite  certain 
influences  of  climate  and  soil  which  produce  substantially 


^  it.. 

\^H 

t^ik^ 

Fig.  38.  —  Washington  Navel  oranges  showing  fluctuations  in  the  navel; 
such  variations  cannot  be  preserved  by  budding. 


the  same  effect  upon  every  plant  of  the  same  variety. 
Navel  oranges  grown  in  the  hot  Imperial  ^'alley  are  much 
redder  in  color  than  those  grown  within  the  influence  of 
ocean  fogs  near  the  coast.  Oranges  grown  on  light  sandy 
soil  are  of  larger  size  than  those  grow^n  on  stiff'  clay  soil. 
Under  the  head  of  fortuitous  variations  mav  be  included 


120  Citrus  Fruits 

many  of  the  common  malforms  and  monstrosities  such  as 
double  oranges,  oranges  with  protruding  navels,  fingered 
lemons,  and  various  other  teratological  curiosities  which 
may  be  found  in  the  cull-heaps  near  the  {)acking-houses. 

IMutations  occur  as  sporting  branches  which  show  a 
different  combination  of  characters  from  the  rest  of  the 
tree.  The  immediate  cause  of  mutations  is  not  at  present 
understood.  They  originate  during  the  division  of  some 
single  cell  in  the  vegetative  tissue  which  results  in 
daughter  cells  containing  the  same  determiners  for  char- 
acters but  segregated  and  recombined  in  such  a  way  as  to 
produce  characters  visibly  different  from  those  of  the 
parent  stock.  Thus  appear  new  characters  which,  from 
the  standpoint  of  the  man  who  is  growing  the  fruit,  may 
be  either  valuable,  neutral,  or  objectionable. 

When  a  shoot  arises  from  tissue  which  has  been  formed 
by  mutating  cells,  the  shoot  represents  a  new  variety  or 
sport  variety  which  may  be  propagated  by  the  ordinary 
method  of  budding.  Sometimes  more  or  less  reversion  to 
the  old  type  occurs  in  the  young  trees.  The  cause  of  this 
has  been  observed  to  be  due  to  the  mode  of  origin  of  the 
sporting  shoot.  If  the  shoot  arises  from  within  the  area  of 
mutating  cells  in  such  a  way  that  only  these  cells  are  used 
in  the  forming  bud,  then  the  resulting  shoot  will  be  com- 
posed exclusively  of  new  cells  and  the  sport  may  be  prop- 
agated true  without  reversion.  If  on  the  other  hand  the 
shoot  arises  on  the  edge  of  the  area  of  new  cells  in  such  a 
way  as  to  include  both  kinds  of  cells  in  its  structure,  then 
there  arises  a  mixed  branch  or  "  sectorial  chimera  "  which 
may  be  expected  to  constantly  produce  branches  of  various 
kinds.     Some  will  be  like  the  original  plant,  some  like  the 


Improvement  of  Citrus  Trees  by  Breeding         121 

new  form,  and  some  in  turn  will  be  mixed  depending  npon 
the  kind  of  cells  occnrring  at  the  point  where  each  bud 
has  its  origin.  The  "  Nomadic  Albinism  "  described  by 
Savastano  '  was  probably  a  sectorial  chimera. 


Fig. 


'■anzo 
).  —  Variegated    sporf.       Note    white    areas 
Volckamer's  "  Hesperides,"  1695. 


leaves.       From 


Sectorial  chimeras  are  not  uncommonly  met  with  in 
citrus  trees.  The  writer  has  found  excellent  specimens 
in  commercial  orchards  and  some  have  been  kept  under 

»  An.  del.  Stazione  de  Agrum.  e.  Fruit.  Vol.  1,  1911,  XXIX. 


122  Citrus  Fruits 

constant  observation  and  study  for  five  years.  A  Valen- 
cia orange  tree  in  an  orchard  near  Whittier  was  evidently 
propagated  from  a  bud  with  mixed  cells,  for  it  still  bears 
year  after  year  on  all  its  branches  both  typical  Valencia 
oranges  and  a  small,  very  rough,  and  worthless  mutation. 
A  twig  here  and  there  will  produce  typical  Valencias,  while 


Fig.  40.  —  A  variegated  sport  of  Valencia  orange.     Notice  white  margin 
of ' 


others  will  produce  curious  mLxed  oranges  having  certain 
sectors  of  the  fruits  composed  of  mutant  tissue.  The 
owner  of  this  tree  endeavored  to  get  rid  of  the  worthless 
type  by  pruning  it  out,  but  mutant  branches  continually 
returned,  and  it  requires  frequent  pruning  to  keep  them 
suppressed.  In  this  case  the  mutant  tissue  happens  to 
occur  irregularly  scattered  or  mixed  with  the  tissue  of  the 


Improvement  of  Citrus  Trees  by  Breeding         123 

original  form.  Such  a  mixture  has  been  called  a  "  hyper- 
chimera."  ' 

Mutations  often  occur  in  the  cells  which  begin  the 
formation  of  the  minute  ovaries  in  the  blossom  buds.  As 
the  ovary  grows  in  size  the  mutation  appears  as  a  sector 
of  the  fruit  which  differs  in  color,  ripening  season,  or  thick- 
ness of  skin  from  the  rest  of  the  fruit.  Such  curious 
fruits  have  been  called  "spontaneous  chimeras."  These 
striped  oranges  and  lemons  are  often  found  by  the  pickers, 
who  usually  incorrectly  attribute  the  phenomena  to  the  in- 
fluence of  cross-pollination.  When  we  consider  that  these 
mutations  are  always  formed  before  pollination  takes  place, 
the  inadequacy  of  the  theory  of  pollen  influence  is  evident. 

When  mutation  occurs  at  the  base  of  the  ovary  it  is  not 
possible  to  continue  it  by  propagation  as  no  buds  occur 
on  the  fruit.  When,  on  the  other  hand,  mutation  occurs 
on  the  trunk  or  branches  in  a  position  where  an  adventi- 
tious bud  may  arise,  then  propagation  is  easy. 

As  before  stated,  many  mutations  showing  various 
types  of  fruit  and  different  bearing  habits  have  occurred 
in  the  orchards,  and  through  ignorant  and  careless  cutting 
of  bud-wood  many  of  the  worthless  forms  have  become 
widely  disseminated  and  now  make  up  a  considerable 
proportion  of  the  trees  in  our  commercial  orchards.  A 
vital  need  at  the  present  time  is  a  careful  study  of  indi- 
vidual trees  by  each  grower,  who  should  determine  which 
trees,  if  any,  belong  to  unprofitable  types  and  top-work 

1 H.  Winkler,  "Uber  Propfbastarde  und  Pflanzliche  Chi- 
maren,"  Ber.  Deuts.  Bot.  Ges.,  25:  568-576.  E.  Baur,  "Propf- 
bastarde, Periklinalchimaren  und  Hyperchimaren, 'Woe.  a7.,  27: 
603-605. 


124 


Citrus  Fruits 


them  to  the  most  desirable  tyi)es.  In  this  way  the  aver- 
age cost  of  production  may  be  greatly  reduced.  The 
great  need  for  a  stufly  of  the  performance  of  individual 
citrus  trees  was  emphasized  by  the  writer  in  1910.'  Since 
then  many  such  studies  have  been  made,  by  far  the  most 
comprehensive  of  which  are  those  of  A.   D.  Shamel.^    Out 

of  a  mass  of  ma- 
terial the  follow- 
ing condensed 
quotations  have 
been  selected 
from  the  studies 
of  J.  II.  Norton/ 
formerly  Super- 
intendent of  the 
Citrus  Experi- 
ment Station  at 
Riverside : 

"The    Navel 
orange    grove 

FiG.41.  — Sectorial  chimera  of  Valencia  orange.       from     which     the 

following  data 
are  taken  is  located  in  West  Highlands,  San  Bernardino 
County.     The  trees  are  the  same  age  and  the  soil  condi- 


1  Coit,  J.  Eliot,  "The  Relation  of  Asexual  or  Bud-Mutation  to 
the  Decadence  of  California  Citrus  Orchards,"  Rpt.  37th 
Cahfornia  Fruit  Growers'  Convention,  1910,  p.  32. 

2  Shamel,  A.  D.,  "A  Study  of  the  Improvement  of  Citrus 
Fruits  through  Bud  Selection,"  U.  S.  Dept.  of  Agriculture, 
Bureau  Plant  Industry,  Circular  No.  77,  1911. 

3  Norton,  J.  H.,  "Variations  in  the  Productivity  of  Citrus 
Trees,"  California  Cultivator,  Vol.  XL,  No.  10,  1913. 


Improvement  of  Citrus  Trees  by  Breeding         125 

tions  uniform.  This  grove  contains  1525  trees  planted 
90  to  the  acre.  The  trees  are  about  16  years  old  and  the 
grove  is  considered  somewhat  above  the  average  in  pro- 
ductiveness, yet  the  trees  vary  in  yield  from  nothing  to 
426  pounds  of  fruit  per  tree. 

"  The  following  is  the  annual  expense  of  this  grove  per 
tree : 

"  General  care  including  taxes,  water,  pruning, 

and  fumigating, $1.14 

Interest  on  Investment, 1.11 

Total  annual  expense  per  tree, .$2.25 

"The  fruit  from  this  grove  was  sold  for  1§  cents  per 
pound  on  the  tree.  The  trees  that  bore  less  than  150 
pounds  of  fruit  were  maintained  at  a  loss,  while  those 
yielding  more  than  150  pounds  paid  a  profit.  This  is 
graphically  shown  in  Figure  44. 

"  The  curved  line  represents  the  yield  per  tree  in  pounds 
arranged  in  the  order  of  yield.  The  horizontal  line  AB  is 
the  *  dead  line,'  and  any  tree  the  yield  of  which  falls 
below  this  line  was  maintained  at  a  loss.  The  shaded 
part  of  the  curved  line  shows  the  trees  that  the  owner 
realized  no  profits  from.  The  shading  above  the  line  AB 
is  due  to  the  loss  sustained  by  the  trees  recorded  below 
the  line.  There  were  490  trees  or  32  per  cent  that  yielded 
less  than  150  pounds  of  fruit.  This  loss  was  made  up  by 
the  profits  from  the  next  646  trees,  that  is,  the  profit  from 
42  per  cent  of  this  grove  was  required  to  offset  the  loss 
sustained  by  32  per  cent.  Seventy-four  per  cent  of  this 
grove  therefore  gave  neither  profit  nor  loss.     This  leaves 


126 


Citrus  Fruits 


the  net  income  to  be  derived  from  .389  trees,  or  26  per  cent 
of  the  grove. 

"  The  total  yield  of  the  gro\c  ^vas  280,254,5  pounds  of 


Fig.  42.  —  Orange  showing  ■^cttoiKil  chimera.     From  Ferrarius,  1646. 

oranges  which  at  l|  cents  a  pound,  gave  a  gross  in- 
come of  S4203.81.  The  expense  was  S3431.25,  leaving  a 
net  income  of  $772.56  or  an  average  net  profit  per  tree  of 


Improvevient  of  Citrus  Trees  by  Breeding 


127 


51  cents.  Could  the  loss  clue  to  the  490  poor  trees  have 
been  eliminated  without  increasing  the  production  per 
tree,  then  the  net  profits  from  the  remaining  1035  trees 
would  have  been  S1125.96  or  SI. 09  per  tree  as  compared 
with  51  cents  profit  per  tree  which  was  actually  the  case." 
The  record  of  this  West  Highlands  orange  grove  may  be 
considered   fairly  typical   of  a   large  proportion   of  the 


Fig.  43.  —  What  is  known  as  the  "wrinkled  sport"  of  Eureka  lemon 
compared  with  normal  fruit.     Both  from  same  tree. 

groves  in  California.  The  differences  of  yield  noted  were 
due  both  to  fluctuations  and  mutations,  but  the  extreme 
differences  were  undoubtedly  due  to  mutations.  The 
average  yield  would  be  greatly  increased  by  top-working 
those  of  the  490  poor  trees  which  proved  to  be  mutative 
to  buds  carefully  selected  from  the  tree  which  yielded 
426  pounds.  Many  of  the  most  progressive  growers 
now    keep   accurate  performance  records  and  top-work 


128  Citrus  Fruits 

the  unprofitable  trees  as  soon  as  they  are  discovered. 
In  the  case  of  the  AustraUan  and  some  other  worthless 
mutations  of  Navel  orange  trees  performance  records  are 
hardly  necessary,  as  any  experienced  man  should  be  able 
to  recognize  such  poor  types  at  a  glance.  For  the  segre- 
gation of  trees  which  represent  undesirable  mutations, 
whose  chief  difference  is  that  of  yield,  the  i)erfomiance 
record  is  indispensable. 

There  is  no  scientific  evidence  to  warrant  the  belief 
that  anything  worth  while  may  be  gained  by  the  selection 
and  propagation  of  trees  whose  high  yield  is  due  to  fluctua- 
tion. It  is  vital  that  the  high  yield  be  due  to  a  true  muta- 
tion in  order  that  the  type  may  be  propagated  and  progress 
made.  As  a  matter  of  fact,  the  standard  type  of  Wash- 
ington Navel  is  normally  a  heavy  bearer  and  the  majority 
of  mutations  observed  are  retrogressive.  It  is  chiefly 
to  counteract  retrogression  that  top-working  is  practiced. 
Occasionally,  however,  mutations  of  peculiar  value  appear. 
The  Thomson  and  the  Navelencia  may  be  cited  as  exam- 
ples. It  is  not  unlikely  that  a  general  increase  in  the 
amount  of  individual  tree  study  by  many  growers  may 
lead  to  the  discovery  of  new  mutations  which  may  be  of 
great  value  to  the  industry.  For  hhn  who  brings  such 
mutations  to  light  is  awaiting  both  honor  and  financial 
reward. 

THE    SELECTION    OF    BUD-WOOD 

The  foregoing  discussion  emphasizes  the  fact  that  the 
selection  of  bud-wood  is  an  exceedingly  important  matter, 
for  if  one  does  everything  else  in  the  most  approved  way 


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130  Citrm  Fruits 

yet  does  not  have  the  kind  of  trees  which  bear  good  fruit, 
he  will  not  have  good  fruit.  This  question  is  of  far  greater 
importance  in  connection  with  citrus  fruits  than  with  de- 
ciduous fruits,  for  it  appears  that  oranges  tend  toward 
mutation  much  more  generally  than  apples  or  peaches. 
On  account  of  failure  to  select  buds  with  due  care  in  the 
past,  a  surprisingly  large  percentage  of  bearing  orange 
trees  are  unprofitable.  The  average  orchard  is  a  mixture 
of  different  types,  some  good,  some  bad.  Every  planter 
should  either  grow  his  own  trees,  or  select  his  own  buds 
and  have  a  nurseryman  grow  the  trees  on  contract,  or  at 
least  buy  trees  from  a  nurser\Tnan  who  has  a  reputation 
for  carefulness  in  the  selection  of  bud-wood. 

It  is  of  the  very  highest  importance  that  all  buds  be  cut 
from  bearing  trees  while  the  fruit  is  on  them  and  from  trees 
which  are  known  to  have  borne  the  ideal  type  of  fruit 
on  each  and  all  of  their  branches  for  a  series  of  years.  It 
is  a  splendid  plan  to  select  certain  typical  mother  trees  in 
the  orchard  and  keep  an  accurate  record  of  the  amount 
and  quality  of  fruit  produced.  If  off-type  fruit  is  borne 
on  any  branch  of  a  tree,  no  buds  should  ever  be  cut  from 
that  tree.  In  the  case  of  the  Navel  orange,  it  happens 
that  the  best  trees  from  which  to  cut  buds  present  only 
fine  fruiting  brush  which  does  not  make  satisfactory  bud- 
wood.  Such  trees  may  be  given  a  moderate  pruning 
and  thinning  out  over  their  whole  tops  and  thus  encour- 
aged to  produce  plump  twigs,  more  suitable  for  bud- 
wood,  the  following  season. 

In  these  days  there  is  much  talk  about  "  pedigreed  " 
nursery  stock.  Usually  what  is  sold  as  pedigreed  stock 
is  stock  whose  scions  are  said  to  have  been  cut  from 


Improvement  of  Citrus  Trees  by  Breeding         131 

a  tree  or  trees  which  are  said  to  have  yielded  exceptionally 
well.  This  is  good  as  far  as  it  goes,  but  it  does  not  fully 
protect  the  buyer  from  ignorant  or  careless  dealers.  The 
unit  of  the  plant  is  not  the  tree ;  it  is  the  cell.  The  term 
"  pedigree  "  may  properly  be  referred  to  animals,  not  to 
plants.  Our  greatest  source  of  mixed  and  worthless  stock 
is  the  irresponsible  amateur  propagators  who  have  been 
operating  so  extensively  on  vacant  city  lots  and  in  yards 
and  gardens  since  the  price  of  trees  has  been  high.  Many 
of  the  trees  produced  in  this  way  are  beautifully  grown 
specimens,  but  the  buyer  should  beware  of  them  unless 
he  can  satisfy  himself  by  personal  investigation  that  the 
buds  have  been  properly  selected. 


CHAPTER  VIII 
JUDGING   CITRUS   FRUITS 

A  GREAT  many  different  scales  have  been  proposed 
from  time  to  time  for  the  judging  of  citrus  fruits.  In 
1892  the  Florida  Horticultural  Society  adopted  an  official 
scale  together  with  rules  and  regulations.  In  1894  the 
Executive  Committee  of  the  Los  Angeles  Chamber  of 
Commerce  adopted  an  official  scale  for  California. 

These  scales,  while  most  excellent  as  ideals  toward 
which  to  work,  are  but  little  used  in  citrus  exhibitions  for 
the  reason  that  their  use  requires  too  much  time.  The 
judges  are  usually  expected  to  judge  hundreds  of  exhibits, 
sometimes  aggregating  twenty  or  more  carloads  of  fruit, 
in  twelve  or  fifteen  hours.  Obviously  it  is  possible  to  use 
the  score-card  only  in  those  classes  where  competition  is 
very  close,  and  in  such  cases  the  great  value  of  the  score- 
card  with  a  fixed  scale  is  clearly  evident. 

The  Florida  rules  require  seven  specimens  to  constitute 
a  plate  entitled  to  entry.  In  California  five  specimens 
are  required. 

Interest  in  citrus  judging  has  been  greatly  stimulated, 
in  California,  by  the  inauguration  in  1911  of  the  National 
Orange  Show,  which  is  held  annually  at  San  Bernardino, 
and  represents,  for  the  Southwest  at  least,  the  citrus  event 
of  the  year. 

132 


Judging  Citrus  Fruits  133 


Orange  Score-card 

Size  (uniformity) 5 

Form  (typiealness) 15 

Stem 5 

Size 3 

Color 2 

Rind 35 

Color 10 

Textm-e 5 

Thickness 5 

Freedom  from  blemishes  15 
Navel  or  seeds 5 

Size  3 

Shape 1 

Prominence 1 

Juice 30 

Abundance 10 

Color 5 

Flavor 15 

Rag 5 

Amount 3 

Character 2 

Total Too 


ORANGE    STANDARDS 

Size.  —  Oranges  for  exhibit  may  be  of  any  size  from  small, 
250's,  to  large,  126's.  The  most  desirable  size  is  medium, 
176's,  which  are  2x11  inches  in  diameter.  Sizing  should  be 
accurate,  one-half  unit  discount  for  each  specimen  varying 
I  inch  from  the  size. 

Form.  —  Fruit  must  have  shape  typical  of  variety  and  be 
free  from  creases  or  corrugations. 

Stem.  —  Stem  must  be  small,  but  close  and  square,  level 
with  surface  of  rind,  sepals  green  and  plump.  For  each 
missing  stem  deduct  one  point. 

Rind.  —  Color  must  be  deep  orange,  the  darker  the  better. 
Bloom  must  be  perceptible ;    texture  smooth  and  fine  with 


134  Citrus  Fruits 

kid-glove  finish  ;  thickness  |  to  jq  inch.  In  discounting  for 
thick  rind  consideration  should  be  given  to  the  length  of 
time  fruit  has  been  picked,  as  rind  gradually  decreases  in 
thickness.  Fruit  must  be  free  from  blemishes  such  as 
insect  injuries,  decay,  wind  scars,  or  abrasions. 

Navel  or  seeds.  —  Navel  marks  to  be  of  good  form  and 
from  1  to  ^  inch  in  diameter.  The  perfect  orange  should 
be  seedless  ;  discount  for  more  than  normal  number  of  seeds 
for  variety. 

Juice.  —  The  largest  possible  amount  of  juice  is  desirable. 
The  perfect  orange  should  sink  in  water.  If  fruit  floats, 
discount  according  to  degree  of  buoyancy.  Color  should 
be  pale  orange  except  in  case  of  blood  oranges,  which  should 
have  deep  red  juice.  Flavor  should  be  fine,  acid  and  sugar 
well  blended,  and  otherwise  characteristic  of  variety. 

Rag.  —  The  less  rag  the  better.  Character  should  be  deli- 
cate and  melting. 

Lemon  Score-card 

Size  (uniformity) 5 

Form  (typicalness) 15 

Stem 5 

Size 3 

Color 2 

Rind 35 

Color 5 

Texture 5 

Thickness 5 

Freedom  from  bitterness     5 

Freedom  from  blemishes  15 

Seeds  (absence) 5 

Juice 30 

Abundance       .     .     .     .15 

Color 5 

Flavor 10 

Rag 5 

Amount 3 

Character 2  

Total 100 


Judging  Citrus  Fruits  135 


LEMON    STANDARDS 

Size.  —  Lemons  may  be  exhibited  in  any  size  from  large, 
2oO's,  to  small,  360's.  The  most  desirable  size  is  the  300, 
which  is  2|  inches  in  diameter.  Sizing  should  be  accurate. 
One-half  unit  discount  for  each  specimen  varying  f  inch  from 
standard. 

Form.  —  Fruit  must  have  shape  typical  of  variety  and  be 
free  from  irregularities.  Sunburned  lemons  are  inequilateral 
and  should  be  heavily  discounted. 

Stem.  —  Stem  must  be  present,  cut  close  and  square, 
sepals  green  and  plump.  For  each  missing  stem  deduct  one 
point. 

Rind.  —  Color  must  be  pale  or  whitish  yellow ;  discount 
for  bronze  tints,  green  marks,  or  sunburn.  Bloom  should  be 
perceptible ;  texture  smooth  and  fine  with  waxlike  finish ; 
strong  and  elastic  with  uninjured  oil  cells.  Thickness  should 
be  from  3^0  to  yV  inch.  Allowance  for  thick  rind  should  be 
made  for  fresh  lemons  when  exhibited.  Just  how  much 
allowance  should  be  made  will  depend  of  course  on  the 
amount  of  curing  the  lemons  have  undergone,  and  this  is 
often  difficult  of  determination  by  any  except  experienced 
persons.      Fruit  must  be  free  from  all  blemishes. 

Seeds.  —  The  perfect  lemon  is  seedless.  Discount  j  point 
for  each  seed. 

Juice.  —  The  largest  possible  amount  of  juice  is  desirable. 
Specific  gravity  should  be  1  (equal  to  that  of  water),  with 
buoyancy  of  |  oz.  allowed  to  large  sizes  and  j  oz.  to  medium 
and  small  sizes  without  discount.  Color  should  be  pale 
lemon  yellow^  Flavor  must  be  clear  and  fine.  Discount 
heavily  for  bitterness  of  rind. 

Rag.  —  The  less  rag  the  better  ;  character  should  be  delicate 
and  tender. 


136  Citrm  FrulU- 

Pomelo  Score-card 

Size  (uniformity) 5 

Form  (typicalness) 10 

Stem 5 

Color 2 

Location 1 

Size 2 

Rind 35 

Color 5 

Texture 5 

Thickness 10 

Smoothness      ....     5 

Freedom  from  blemishes  10 

Seeds  (number) 10 

Juice 25 

Abundance 10 

Color 5 

Flavor 10 

Rag  (tenderness) 10 

Total 100 

POMELO    STANDARDS 

Size.  —  Pomelos  may  be  exhibited  in  any  size  from  large, 
28's,  to  small,  96's.  The  most  desirable  size  is  the  54,  in  which 
the  fruits  are  4h  inches  in  diameter.  Sizing  should  be 
accurate.  One-half  unit  discount  for  each  fruit  varying 
J  inch  from  standard. 

Form.  —  Fruit  must  have  shape  typical  of  variety  and  be 
free  from  irregularities. 

Stem.  —  Stem  must  be  present,  cut  close  and  square,  sepals 
green  and  plump.     For  each  missing  stem  deduct  one  point. 

Rind.  —  The  color  should  be  ivory  white,  the  texture 
smooth  and  fine.  Thickness  should  l)e  I  to  fV  inch.  Fruit 
must  be  free  from  all  blemishes. 

Seeds.  —  Seedlessness  is  the  standard  for  pomelos.  Cut 
I  point  for  each  average  seed  per  fruit. 


Judging  Citrus  Fruits  137 

Juice.  —  The  largest  possible  amount  of  juice  is  desirable. 
When  placed  in  water  the  fruit  should  not  rise  more  than 
J  inch  above  the  water.  Flavor  must  be  characteristic  of 
the  variety  with  acidity  and  sweetness  well  blended. 

Rag.  —  Rag  should  be  tender  enough  to  cut  easily  with  a 
spoon. 

Score-card  for  Packed  Boxes 

Exterior  appearance 40 

Cleanliness 10 

Neatness 5 

Artistic  quality  of  label     10 

Size  and  placing    ...   10 

Stenciling 5 

Nailing        20 

Position  of  cover  ...     5 

Position  of  cleats  ...     5 

Placing  of  nails      ...     5 

Placing  of  strap  ...  5 
Wrapping 20 

Quality  of  paper    ...     7 

Artistic  quality  of  design    7 

Twist 6 

•Placing        20 

Facing 5 

Alignment 5 

Firmness 5 

Crown 5 

Total        100 


STANDARDS  FOR  PACKED  BOXES 

Appearance.  —  Box  material  must  be  perfectly  bright  and 
clean  and  put  together  in  a  neat  manner.  The  lithograph 
label  must  have  artistic  color  qualities  ;  it  should  be  of  original 
design,  and  the  illustrations  should  be  true  to  life.  Box 
labels  should  be  exactly  10  X  H  inches  for  oranges  and 
10  X  13  inches  for  lemons,  including  a  j  inch  border  in  each 


138  Citrus  Fruits 

ciise.  Combination  labels  are  to  be  discounted.  Labels 
should  be  placed  flush  with  bottom  of  box,  leaving  space 
at  top  for  stamping.  This  strip  of  bare  wood  should  show 
the  impressions  of  three  rubber  stamps  as  follows :  in  the 
right-hand  corner,  the  number  of  fruit  in  the  box ;  in  the 
center,  the  variety  of  oranges  or  pomelos,  and  in  the  left- 
hand  corner,  the  number  of  the  packer.  The  name  of  the 
variety  of  lemons  is  not  placed  on  the  box  for  reasons  ex- 
plained in  Chapter  XVI. 

Nailing.  —  The  cover  pieces  must  be  perfectly  parallel 
and  the  cleats  must  be  above  the  cover.  Cleats  below 
the  cover  should  debar  the  box  from  exhibit.  Nails  must 
be  properly  placed  and  driven  home  without  showing  print 
of  hammer  in  wood. 

Wrapping.  —  Paper  should  be  strong  and  of  good  quality. 
Design  should  be  artistic,  and  the  twist  should  be  carefully 
made. 

Placing.  —  On  placing  fruit  in  the  boxes  the  design  on  the 
wrapping  paper  should  be  made  to  face  the  openings  in  the 
side  of  the  box.  The  alignment  should  be  as  nearly  perfect 
as  possible.  Fruit  should  be  firmly  placed  and  the  standard 
amount  of  crown  is  1  inch  at  center. 

Score  Card  for  Feature  Exhibits 

Quantity  and  quality  of  fruit    ....  50 

Artistic  qualities  of  plant  decoration       .  15 

Bunting  and  electric  effects        ....  15 

Originality  of  design 10 

Unity  of  expression 10 

Total 100 


CHAPTER  IX 

SELECTION   OF   SITE   AND    PREPARATION 
FOR   PLANTING 

Success  with  citrus  fruits  depends  to  a  very  large  ex- 
tent upon  the  proper  selection  of  the  site  for  the  orchard. 
This  is  especially  true  in  countries  where  the  climatic  and 
soil  conditions  vary  widely  in  the  same  locality.  It  is 
poor  policy  to  examine  a  piece  of  land  or  a  bearing 
orchard  without  a  program.  This  is  especially  true  when 
different  propositions  are  to  be  contrasted  with  a  view  to 
deciding  on  a  purchase. 

It  is  suggested  that  the  following  list  of  points  be  noted 
in  going  over  every  piece  of  land.  Each  point  may  be 
weighted  after  the  fashion  of  a  score-card  and  thus  accu- 
rate comparisons  between  the  different  properties  exam- 
ined made  easier. 

PROPOSED    SCORE-CARD    FOR    CITRUS    LANDS 

1.  Price  per  acre. 

2.  Freedom  from  frost. 
Legal  right. 


3.  Water 


Amount. 
Quality. 
Cost.  ' 

139 


140  Citrus  Fruits 

4.  Continuity  of  tr<act. 

5.  Quality  and  kind  of  soil. 

6.  Drainage  outlet. 

7.  Freedom  from  hardpan. 

8.  Freedom  from  stones  and  brush. 

9.  Freedom  from  alkali. 

10.  Freedom  from  waste  land. 

11.  Susceptibility  to  wind. 

12.  Nearness  to  town. 

13.  Nearness  to  packing-houses. 

14.  Quality  of  roads. 

15.  Distance  from  scale  infested  orchard. 

Additional  Points  for  Bearing  Orchards 

16.  Freedom  from  scale  and  diseases. 

17.  Freedom  from  mottled-leaf. 

18.  Uniformity  of  trees  and  record  of  yield. 

19.  Condition  of  trees  as  to  pruning. 

20.  Adaptation  of  variety  to  district. 

THE    FROST    QUESTION 

One  of  the  most  important  factors  limiting  the  growth  of 
citrus  fruits  is  frost.  The  frost  hazard  of  any  given  piece 
of  land  is  at  best  a  very  uncertain  quantity  and  may  be 
judged  only  approximately  even  after  years  of  experience 
and  observation.  Within  the  established  citrus  districts, 
as  a  rule,  the  elevated  slopes  of  the  foothills,  preferably 
with  a  southern  or  western  exposure,  at  an  elevation  of 
from  500  to  1500  feet  above  sea  level  and  100  to  500  feet 
or  more  above  the  bottom  or  "draw"  of  the  valley,  are 
the  most  frost-free  locations.     On  lands  subject  to  heavy 


Selection  of  Site  and  Preparation  for  Planting    141 

frosts  every  year,  the  expense  of  orchard  heating  would  be 
too  great.  Usually  the  heavy  cold  air  flows  down  and  col- 
lects in  the  valleys,  leaving  the  higher  lands  above  the 
frost  line.  There  are  notable  exceptions  to  this  general 
rule,  however,  for  when  the  drop  in  temperature  is  ac- 
companied by  strong  winds,  as  was  the  case  during  the 
blizzard  of  January,  1913,  the  high  and  supposedly  frost 
free  land  may  suffer  most  of  all.  Such  blizzards  are 
fortunately  of  extremely  rare  occurrence. 

The  frost  hazard  .of  any  given  piece  of  land  (except  that 
which  is  closely  surrounded  by  old  citrus  groves)  can 
only  be  found  by  exposing  self-registering  thermometers 
for  several  winters.  If  there  are  homesteads  with  yards 
and  gardens  in  the  vicinity,  a  study  of  the  flowering  plants 
may  give  some  idea  of  the  frost  hazard.  For  example, 
if  old  and  well  established  plants  of  bougainvillsea,  Sola- 
niim  wenlandii,  poinsettia,  or  jacaranda  are  found  which 
show  no  signs  of  having  been  killed  back,  it  is  fairly  certain 
that  a  lemon  orchard  in  the  immediate  vicinity  would  not 
be  injured  except  perhaps  in  occasional  and  exceptional 
years. 

THE    WATER   SUPPLY 

In  no  citrus  district  of  California  is  the  rainfall  sufficient 
for  irrigation.  The  amount  of  water  needed  under  different 
conditions  will  be  discussed  in  Chapter  XII,  but  it  may  be 
well  to  point  out  here  that  it  behooves  the  buyer  of  citrus 
land  or  orchards  to  make  a  careful  study  of  the  character 
of  the  water  supply.  He  should  bear  in  mind  that  upon 
the  water  supply  depends  the  life  of  the  trees  and  that  he 
should  thoroughly  understand  the  system  of  which  his 


142  CitriLs  Fruitf 

ranch  is  a  part.  Water  rights  in  an  irrigated  country  are 
often  complicated  and  one  should  familiarize  himself  not 
only  with  the  legal  details,  but  with  the  present  physical 
condition  of  the  entire  system. 

In  localities  in  which  the  water  is  ])umped  from  wells 
located  in  the  groves  it  is  not  uncommon  for  the  gradual 
increase  in  use  of  water,  which  takes  place  as  the  planting 
in  the  neighborhood  increases,  to  lower  the  water  table  to 
such  an  extent  that  the  old  wells  have  to  be  dug  deeper 
and  pumps  of  higher  power  installed.  The  indications 
are  that  as  the  industry  grows  and  the  value  of  water 
increases  the  number  of  law-suits  will  increase  rather  than 
diminish.  The  best  w^ater  right  is  a  share  in  an  old  and 
well  established  canal  company  which  holds  prior  rights 
and  draws  its  supply  from  the  melting  snows  on  the 
mountains,  and  which  guarantees  the  delivery  of  a  certain 
number  of  miner's  inches  per  month  per  share. 


SOIL    ADAPTATIONS 

California  soils  are  famed  for  their  great  depth  and 
fertility,  and  the  soils  of  the  citrus  belt  are  no  exception 
to  the  rule.  There  is  a  wonderful  variation,  however, 
in  the  kinds  of  soil  now  occupied  by  citrus  groves. 

We  have  the  fine  sandy  soil  of  Anaheim,  the  bluish 
muck  soils  of  Santa  Paula,  the  black  adobe  of  La  Habra, 
the  gravelly  loam  of  Upland,  the  disintegrated  granite 
of  Riverside,  the  red  loam  of  Redlands,  the  dry-bog  of 
Porterville,  the  red  adobe  of  Fairoaks,  and  the  soft  desert 
soils  of  Imperial.  Citrus  trees  are  now  growing  success- 
fully in  all  of  these  soils  and  do  not  seem  to  be  particularly 


Selection  of  Site  and  Preparation  for  Planting     143 

partial  to  any  one  kind  so  long  as  the  physical  conditions 
are  good.  Of  course  it  is  easier  as  well  as  cheaper  to  culti- 
vate a  soft  sandy  loam  than  a  sticky  adobe,  and  easily 
worked  soils  are  much  more  desirable  from  the  standpoint 
of  the  man  who  is  to  till  them. 

What  are  these  conditions  then  which  make  for  success 
or  failure  and  are  more  important  than  the  type  of  the  soil  ? 
In  the  first  place,  nothing  is  more  fatal  to  success  than  to 
judge  the  value  of  a  piece  of  ground  by  the  nature  of  the 
surface  soil.  By  digging  or  boring  down  to  a  depth  of  a 
few  inches  or  feet,  something  entirely  different  from  that 
seen  on  top  may  be  encountered,  which  would  doom  the 
proposed  planting  to  eventual  failure. 

It  is  not  uncommon  to  find  subsoils  so  hard  that  it  is 
impossible  for  water  and  tree  roots  to  penetrate  them.  On 
such  soils  trees  are  greatly  restricted  in  their  root  develop- 
ment and  the  reservoir  for  water  is  much  reduced.  Such 
soils  are  apt  to  be  too  wet  in  the  rainy  season  and  are  very 
difficult  to  irrigate  properly. 

On  the  other  hand,  the  subsoil  may  be  too  coarse  and 
open,  unretentive  of  moisture,  and  deficient  in  plant  food. 
Both  heavy  and  light  soils  have  advantages  peculiar  to 
themselves  and  a  compromise  between  them,  usually  known 
as  sandy  loam,  is  nearly  always  the  most  desirable. 

To  sum  up,  then,  the  soil  for  a  citrus  orchard  may  be 
of  any  type,  preferably  a  sandy  loam  ;  but  it  must  be  at 
least  four  or  five  feet  deep  ;  it  must  be  free  from  hardpan 
or  strata  of  coarse  gravel ;  it  must  be  well  drained ;  and  it 
should  be  so  situated  as  to  make  irrigation  easy.  In  some 
cases  a  thin  stratum  of  hardpan  a  foot  or  two  below  the 
surface  may  be  broken  up  with  dynamite  before  the  trees 


144  Citrus  Fruits 

are  planted.  This  allows  the  roots  and  the  Avater  to  get 
through  and  may  sometimes  make  otherwise  undesirable 
land  available  for  citrus  trees. 

Of  the  two  most  common  conditions,  a  light  surface 
soil  over  heavy  clay  subsoil  is  more  to  be  desired  than  a 
heavy  clay  surface  soil  over  sand  or  gravel. 

The  ideal  soil  is  a  rich,  nearly  level,  friable,  easily  worked 
loam,  eight  or  more  feet  deep,  growing  gradually  lighter  as 
the  depth  increases.  This  not  only  i)r()vides  a  great  store- 
house of  plant  food,  but  a  great  reservoir  to  hold  water. 

Alkali  soils  commonly  occur  on  the  floors  of  the  valleys 
where  it  is  usually  too  frosty  for  citrus  trees.  Occa- 
sionally, however,  the  question  arises  as  to  the  suscepti- 
bility of  citrus  trees  to  alkali.  Where  the  soil  contains 
two-tenths  of  one  per  cent  of  total  salts,  the  trees  are 
likely  to  be  injuriously  affected.  A  total  salt  content 
of  less  than  one-tenth  of  one  per  cent  is  usually  con- 
sidered safe.  These  figures  will  be  found  to  vary  some, 
however,  according  to  the  proportions  of  the  different 
salts  which  taken  together  are  known  as  "alkali,"  some  of 
which  (such  as  sodium  carbonate)  are  much  more  injurious 
than  others. 

So-called  acid  soils  are  very  rare  in  the  citrus  districts  of 
the  West.  They  are  more  apt  to  occur  in  wet,  swampy 
land,  or  in  recently  cleared  forest  soil,  where  there  is  a 
large  amount  of  vegetable  matter  in  the  ground.  Such  a 
condition  can  be  definitely  determined  by  chemical 
analysis.  Soil  acidity  is  easily  corrected  by  an  application 
of  lime. 

The  question  of  the  disposition  of  waste  water  is  an  im- 
portant one,  as  in  many  places  there  are  stringent  laws 


Selection  of  Site  and  Preparation  for  Planting    145 

against  allowing  it  to  flow  into  the  roads  or  on  to  a  neigh- 
bor's land.  Theoretically  there  should  be  no  waste  water, 
as  it  should  all  be  used  on  the  land.  In  many  cases, 
however,  and  especially  on  clay  soil  and  with  careless 
laborers,  a  certain  amount  of  water  will  escape  from  the 
lower  ends  of  the  furrows  and  it  may  become  necessary  to 
dig  a  long  ditch  or  even  put  in  a  very  expensive  pipe  line 
to  dispose  of  this  waste  water. 

The  question  of  insect  pests  should  also  be  considered. 
A  location  far  from  any  scale-infested  orchard  may  mean 
that  fumigation  may  not  be  necessary  for  many  years, 
if  at  all,  whereas  a  site  on  the  windward  side  of  a  badly 
infested  orchard  will  mean  fumigation  almost  from  the 
first,  with  all  the  attendant  bother  and  expense. 

Not  the  least  important  point  to  consider  is  the  nearness 
to  the  railroad  and  packing-house,  and  the  condition  of 
the  roads  over  which  the  fruit  must  be  hauled.  The  labor 
problem  also  is  important.  Orchards  near  small  towns 
have  the  advantage  of  a  larger  and  more  dependable  labor 
supply,  and  this  is  quite  an  advantage  at  picking  time  and 
especially  when  frost  fighting  becomes  necessary. 

Clearing  any  leveling.  —  For  reasons  pointed  out  in  Chap- 
ter XXI,  it  is  very  important  in  clearing  land  for  citrus 
trees  to  dig  the  old  trees  out  by  the  roots,  being  careful 
to  get  out  all  the  large  roots  to  a  depth  of  several  feet. 
Especially  is  this  true  where  oak  or  sycamore  trees  have 
occupied  the  land,  for  the  roots  of  these  trees  are  especially 
apt  to  harbor  the  Armellaria  fungus  for  many  years. 

On  account  of  the  high  price  of  well  located  citrus  land, 
it  has  become  profitable  to  develop  very  stony  ground.  All 
the  stones  above  the  size  of  an  orange  are  hauled  out  and 


146  Citrus  Fruits 

built  into  walls  or  used  in  road  construction.  The  land 
is  then  deeply  plowed  and  the  stones  picked  up  again,  this 
process  being  continued  till  all  the  stones  are  removed  to  a 
depth  of  ten  or  twelve  inches,  A  good  deal  of  such  land 
proves  very  fertile  and  produces  high  class  fruit. 

After  the  land  is  cleared,  it  must  be  leveled  with 
"  Fresno  "  or  other  scrapers  until  the  surface  presents  a 
uniform  grade.  This  is  very  important,  for  otherwise 
the  irrigation  water  will  run  through  different  parts  of  the 
rows  at  different  rates  of  speed,  and  consequently  sink  to 
unequal  depths,  with  the  result  that  some  trees  get  too 
much  water  while  others  do  not  get  enough.  On  spots 
where  hardpan  is  encountered,  especially  on  knolls  from 
which  the  soil  is  removed  to  fill  up  depressions,  the  condi- 
tions may  be  greatly  improved  by  blasting  and  breaking 
up  the  hardpan  in  order  that  the  water  and  roots  may  get 
through.  The  cost  of  blasting  will  vary  with  the  thick- 
ness and  depth  of  the  hardpan.  For  instance,  when  a 
stratum  six  inches  thick  lies  four  feet  below  the  surface, 
it  will  require  tw^o  sticks  or  one  pound  of  25  per  cent  dyna- 
mite, four  feet  of  fuse,  and  a  cap.  The  cost  of  materials 
and  labor  will  amount  to  about  25  cents  per  tree,  the 
charges  being  placed  only  where  the  trees  are  to  stand.  If 
the  ground  is  quite  dry,  as  it  should  be,  when  the  work  is 
done  the  shattering  effect  will  extend  for  about  five  feet 
in  all  directions.  The  chunks  of  hardpan  which  are 
loosened  should  be  removed  from  the  holes  before  the  trees 
are  planted. 


CHAPTER  X 

PLANTING   THE  ORCHARD 

After  the  ground  has  been  properly  leveled,  it  should 
be  put  in  the  best  of  tilth  by  deep  plowing  and  cultivat- 
ing. It  is  a  good  plan  to  plow  deeply  in  the  fall  and  leave 
the  land  rough  during  the  rains  of  winter.  In  spring, 
the  volunteer  crop  of  weeds  and  grass  may  be  turned 
under  and  the  land  harrowed  and  dragged.  This  will 
leave  the  land  smooth  and  in  excellent  condition  for 
staking  out  the  orchard. 

ORCHARD    PLANS 

There  are  three  objects  to  be  considered  in  laying  out 
the  orchard  :  symmetry  of  appearance,  economy  of  space, 
and  facility  for  future  care.  On  level  land,  of  course,  the 
first  step  is  to  set  the  trees  in  straight  rows  and  at  equal 
distances  apart.  There  are  various  methods  of  disposing 
of  the  straight  row,  however,  and  these  methods  all  have 
their  advocates,  and  each  one  its  advantages.  The  most 
important  of  these  are  the  triangular,  square,  hexagonal, 
and  quincunx. 

In  the  triangular  system,  the  trees  are  set  in  rows  but 
the  first  tree  in  every  second  row  is  set  not  on  the  line 
but  is  moved  in  half  the  distance  between  trees.  By  this 
147 


metbM  more 


Citrus  Fruits 


more  room  is  given  the  trees  and  a  less  number 
fanted  to  tlie  acre  than  by  the  square  method,  but 
C,\^  is  possible  to  cultivate  and  even  irrigate  three  ways 
through  the  orchard.  In  laying  out  the  orchard,  the 
ground  is  first  laid  out  in  squares,  after  which  a  line  is  run 
diagonalh'  across  the  field  and  a  tree  stake  placed  wherever 
this  line  passes  through  the  corners  or  cuts  the  side  of  a 
square. 

The  square  system  is  by  far  the  most  commonly  used, 
and  may  be  followed  either  for  squares  or  oblong  rectangles. 
The  rows  of  trees  intersect  each  other  at  right  angles  and 
cultivation  may  be  carried  on  in  two  directions. 

By  the  hexagonal  system,  the  trees  are  set  equidistant 
from  each  other.  Six  trees  form  a  hexagon  with  a  seventh 
in  the  center.  By  this  means  the  ground  is  more  eco- 
nomically divided  and  more  trees  are  planted  per  acre 
at  a  given  distance  apart  than  by  any  other  method. 

By  the  quincunx  system  four  trees  constitute  a  square 
with  a  fifth  in  the  center,  thus  doubling  the  number  of 
rows.  This  method  is  chiefly  used  in  planting  with  the 
idea  of  removing  the  center  trees,  which  are  usually  of 
dwarf  varieties,  when  those  designed  to  be  permanent 
shall  have  attained  a  considerable  size.  The  orchard 
then  assumes  the  square  plan. 

The  quincunx  system  is  rarely  used  in  planting  citrus 
orchards  as  it  is  not  customary  to  use  other  and  smaller 
varieties  of  fruit  trees  as  temporary  fillers  in  citrus  or- 
chards. 

The  following  table  gives  the  number  of  trees  required 
to  plant  an  acre  at  various  distances  apart  according  to 
each  of  the  above  four  plans : 


Planting  the  Orchard 


149 


Number  of  Trees  to  the  Acre 


Distance  Apart 

Quincunx 

Hexagonal 

Square 

Triangular 

35  X  35  feet 

65 

41 

36 

33 

30  X  30  feet 

83 

55 

48 

44 

25  X  25  feet 

126 

81 

70 

64 

25  X  20  feet 

87 

79 

24  X  24  feet 

137 

86 

76 

22  X  22  feet 

173 

103 

90 

20  X  20  feet 

199 

126 

108 

98 

18  X  18  feet 

247 

142 

134 

122 

20  X  15  feet 

145 

132 

There  is  a  good  deal  of  variation  throughout  CaHfornia 
in  regard  to  the  distances  at  which  citrus  trees  are  planted. 
The  following  are  the  usual  distances  which  give  the  best 
results:  kumquats,  12  X  12  feet;  tangerines,  20  X  20 
feet ;  Navel  oranges,  22  X  22  feet ;  and  Valencia  oranges, 
lemons,  and  pomelos,  24  X  24  feet.  Lemons  sometimes 
bear  well  and  produce  a  larger  tonnage  per  acre  w4ien 
planted  close  in  one  direction.  The  old  Eureka  orchard 
at  the  Limoneira  Ranch  near  Santa  Paula,  which  is  planted 
26  X  15  feet,  is  a  notable  example  of  this. 

Many  citrus  growers  prefer  to  employ  a  surveyor  to 
laj^  out  the  orchard  and  set  the  stakes  which  mark  the 
points  where  the  trees  are  to  stand.  While  this  is  a  good 
plan  with  large  plantings,  especially  where  the  ground  is 
rolling,  it  is  not  necessary  in  the  case  of  five  or  ten  acre 
blocks.  A  satisfactory  w^ay  to  lay  out  a  small  tract  is  by 
means  of  a  strong  wire  as  long  as  the  tract  is  wide.     This 

'  Adapted  from  Hume,  Bailey,  and  Wickson. 


150  Citnis  Fruits 

should  be  carefully  measured  and  a  button  soldered  to 
the  wire  for  each  tree  row.  After  the  stakes  are  set  along 
each  side  of  the  field  marking  the  rows,  the  wire  may  be 
stretched  between  each  pair  and  thus  carried  across  the 
field,  a  stake  being  set  at  every  point  to  be  occupied  by  a 
tree. 

Much  of  the  land  available  for  citrus  planting  is  entirely 
too  steep  and  broken  to  admit  of  any  of  the  plans  above 
mentioned.  Such  lands  are  often  of  great  value  on  ac- 
count of  their  freedom  from  frost.  In  such  cases  the  rows 
are  laid  off  on  contours.  By  this  means  the  irrigation 
furrows  are  run  on  a  more  uniform  grade  throughout  their 
length,  and  the  storm  water  problem  is  solved,  since  the 
water  which  accumulates  in  each  row  will  be  carried  off 
separately  to  the  side  of  the  field  and  safely  disposed  of. 

Where  the  general  slope  of  the  land  is  not  more  than 
15  per  cent,  cultivation  may  be  carried  on  at  right  angles 
to  the  irrigation  furrows  after  a  slight  ridge  has  been 
established  in  the  tree  row.  In  order  to  facilitate  orchard 
operations  it  is  wise  to  arrange  the  trees  in  rows  running 
up  and  down  the  hill. 

On  very  steep  hillsides  it  is  necessary  to  build  terraces 
and  in  such  cases  the  trees  are  planted  on  the  brink  and 
cultivation  and  irrigation  is  limited  to  one  side  of  the 
tree  row.  The  terrace  banks  should  be  planted  w4th 
some  hardy  plant  which  will  displace  weeds  and  prevent 
washing.  In  coast  counties  where  the  air  is  moist  Mesem- 
bryanthemum  australis  (white  flowered)  or  M.  roseum 
(pink  flowered)  are  recommended.  In  interior  valleys 
perhaps  Lippia  may  be  used  for  this  purpose. 

Irrigation  water  is  usually  conducted  in  a  pipe  line 


Planting  the  Orchard  151 

along  the  crest  of  a  ridge  with  contours  or  terraces  diverg- 
ing on  either  side  at  irregidar  intervals.  Where  the  con- 
tours converge  to  within  less  than  twenty  feet  the  trees 
are  omitted. 

Contours  may  be  easily  laid  out  by  the  use  of  a  twenty- 
five  foot  j)lank  to  which  a  carpenter's  spirit-level  is 
attached.  One  end  is  equipped  with  an  adjustable  leg 
or  shoe  upon  which  is  marked  off  a  scale  to  hundredths 
of  a  foot.  By  adjusting  the  length  of  the  leg  for  the 
desired  grade  and  pivoting  on  the  other  end,  the  shoe 
can  be  located  on  the  next  point  of  the  grade  by  trial, 
the  main  plank  being  kept  level  as  determined  by  the 
spirit-level.  The  grade  established  will  depend  a  good 
deal  upon  the  character  of  the  soil  and  the  nature  of  the 
slope,  inasmuch  as  some  soils  tend  to  wash  much  more 
easily  than  others. 

Time  of  planting.  —  As  explained  in  a  previous  chapter, 
citrus  trees  have  three  more  or  less  distinct  periods  of 
growth  during  the  year.  It  is  not  wise  to  transplant  the 
trees  during  one  of  these  periods  of  growth.  They  may 
be  planted  at  any  t!me  of  year,  but  should  be  as  nearly 
dormant  as  possible.  The  most  convenient  as  well  as 
the  customary  time  of  planting  in  California  is  between 
April  1  and  June  15,  preferably  during  the  month  of  May 
or  just  after  completion  of  the  first  growth  and  before 
the  starting  of  the  second. 


ROOT-STOCKS 

While  there  are  at  least  seven  possible  root-stocks  upon 
which  citrus  trees  may  be  grown,  there  are  only  three  which 


152  Citrus  Fruits 

are  used  commercially  in  California  at  the  present  time, 
viz. :  the  sour  or  bitter,  the  sweet,  and  the  pomelo.  It  is 
said  that  at  present,  practically  every  citrus  tree  in 
Europe  is  grown  on  the  sour-stock.  Perhaps  we  would 
be  safe  in  saying  that  every  tree  in  California  would  be 
as  well  off  on  sour-stock,  yet  there  are  a  few  people  who 
still  claim  that,  in  certain  situations,  sweet-stock  is  best, 
at  least  for  oranges.  All  lemons  should  be  grown  on  sour- 
stock  on  account  of  its  great  resistance  to  brown-rot 
gumming.  Sour-stock  should  be  used  for  oranges  and 
pomelos  on  low,  heavy,  or  wet  soils.  On  high,  dry,  well- 
drained  soil  sweet-stock  is  practically  as  good  but  ap- 
parently no  better  for  oranges.  Orange  trees  will  make 
a  quicker  start  into  growth  and  begin  to  bear  fruit  a  little 
earlier  on  sweet-stock,  but  after  the  trees  are  six  or  seven 
years  old  no  one  can  tell  any  difference  in  the  size  or 
fruitfulness  of  the  trees.  The  sour-stock  has  the  advan- 
tage, therefore,  in  being  more  resistant  to  gum  diseases 
and  foot-rot  of  various  kinds. 

The  use  of  pomelo  stock  is  increasing  somewhat,  although 
it  has  not  been  widely  experimented  with.  It  is  giving 
pronounced  success  where  used  for  lemons  on  open 
gravelly  soils  in  the  interior  valleys.  Pomelo  seedlings 
often  give  trouble  in  the  seed-bed  by  gumming  and  by 
their  peculiar  habit  of  blooming  and  setting  fruit  when 
they  are  only  two  or  three  inches  high. 

In  addition  to  the  above  three  stocks  there  are  several 
others  which  are  entitled  to  mention  for  the  reason  that 
while  they  may  be  no  longer  used  in  propagation  they 
are  often  met  with  in  old  orchards.  The  rough  lemon  is 
said  to  be  hardy  and  to  a  certain  extent  drought-resistant, 


Planting  the  Orchard  153 

and  is  being  experimented  with.  It  will  probably  not 
gain  favor,  however,  as  it  is  very  susceptible  to  brown-rot 
gumming. 

TrifoKate  stock  is  largely  used  in  Florida,  and  in  the 
citrus  districts  of  Louisiana  and  Texas  it  is  used  almost 
exclusively  for  growing  the  Satsuma  orange,  which  does 
very  well  on  this  stock.  In  California,  however,  trifoliate 
is  but  little  used.     There  remain  a  few  old  orange  and 


teitiop  ill  young  leiiiuii  oiili 


pomelo  orchards  upon  it  w^hich  are  doing  fairly  well,  but 
failures  are  more  frequent  than  successes,  and  in  very  few 
cases  does  it  appear  to  show  any  advantage  over  the  sour 
or  sweet.  In  some  places  Navel  oranges  sweeten  earlier 
in  the  fall  when  grown  on  trifoliate  stock.  Perhaps  the 
trifoliate  comes  nearest  being  a  success  when  used  on 
heavy  soil  in  the  Tulare  district.  Trifoliate  is  very  ob- 
jectionable for  lemon  trees  and  has  been  an  absolute  failure 
in  every  case  recorded  in  California. 


154  Citrus  Fruits 

Chinese  lemon,  a  form  of  citron,  was  once  used  to  some 
extent  but  has  long  been  abandoned  entirely.  It  forced 
the  tree  into  an  extremely  rapid  growth  which  resulted 
in  coarse  fruit.  It  was  short  lived  and  quite  susceptible 
to  various  root  decays. 

Ordinary  lemon  stock  was  sometimes  used  in  the  early 
days.  Instead  of  growing  seedlings  and  budding  upon 
them,  some  of  the  early  planters  simply  rooted  cuttings 
of  the  variety  desired  and  set  them  out  in  the  orchard.  A 
few  of  these  old  trees  remain,  but  their  record  does  not 
furnish  a  good  recommendation  for  this  stock,  as  the 
trees  are  nearly  always  more  or  less  affected  with  root-rot. 
But  aside  from  root-rot  lemon  roots  have  clearly  shown 
their  inferiority.  The  bud  unions  of  certain  lemon  trees 
at  the  Limoneira  Ranch  became  buried  with  soil  and 
one  or  two  roots  put  out  from  above  the  bud.  Such  trees 
showed  a  distinct  depreciation  in  the  amount  and  quality 
of  fruit  and  vigor  of  foliage.  Where  only  one  large  lemon 
root  put  out,  the  tree  shows  the  effects  on  that  side  only, 
and  this  was  the  case  even  w^hen  the  lemon  root  was  ap- 
parently healthy  and  vigorous. 

The  question  is  sometimes  asked  as  to  whether  the 
fruit  of  the  orange  will  be  deleteriously  affected  by  the  sap 
passing  through  a  section  of  lemon  wood  as  is  the  case 
when  budded  lemon  trees  are  top-worked  to  oranges.  A 
large  number  of  instances  of  this  have  been  reported  on, 
and  in  no  case  does  there  seem  to  be  any  injury  or  reduc- 
tion in  quality  of  the  oranges  from  having  grown  on  lemon 
trunks. 

Oranges  are  never  grown  from  cuttings  for  the  reason 
that  orange  cuttings  cannot  be  induced  to  strike  root. 


Planting  the  Orchard  155 

There  has  been  much  difference  of  opinion  and  dis- 
cussion of  the  point  as  to  whether  or  not  the  hardiness  of 
a  cold  resisting  stock,  such  as  the  trifohate,  was  trans- 
mitted to  the  scion.  PubHshed  reports  ^  indicate  that 
such  has  been  the  case  in  Florida.  In  California  such  an 
effect,  if  present  at  all,  is  so  slight  as  to  be  hardly  worth 
recording.  Rows  of  several  varieties  of  trees  on  each  of 
the  different  stocks  have  been  grown  for  years  at  the 
Citrus  Experiment  Station  at  Riverside  and  have  passed 
through  two  periods  of  excessive  cold.  After  a  very 
critical  examination  of  the  trees,  the  writer  was  forced  to 
the  conclusion  that,  in  this  case  at  least,  there  was  prac- 
tically no  difference  in  the  amount  of  injury  from  cold 
sustained  by  the  trees  on  the  different  stocks. 


DIGGING    THE    HOLES 

Before  the  holes  are  dug,  the  notched  planting-board 
should  always  be  used  in  order  to  be  able  to  set  the  tree 
in  the  hole  in  the  exact  position  previously  occupied  by 
the  stake.  Large  holes  should  be  dug,  two  feet  wide  and 
one  and  a  half  feet  deep.  The  bottom  of  the  hole  should 
be  carefully  inspected  for  stone  or  hardpan  and  should 
be  well  loosened  up  either  with  the  spade  or  with  a  charge 
of  explosive.  If  the  trees  come  with  bare  roots,  they 
should  be  handled  with  extreme  care  to  prevent  drying 
out. 

It  is  customary  to  puddle  the  roots  of  trees  when  they 
are  not  balled.     This  puddling  is  done  at  the  nursery  and 

1  G.  L.  Taber,  Florida  Farmer  and  Fruit-Grower,  1901. 


156 


Citrus  Fruits 


decreases  to  a  small  extent  the  susceptibility  to  injury 
from  drying  while  handling  in  the  field.  The  roots  should 
be  trimmed,  all  broken  ends  being  cut  off  smooth,  and  the 
soil  sifted  in  around  the  roots  so  as  to  leave  no  air  holes. 

This  soil  should 
be  moist  and  fine 
and  must  always 
be  well  tramped 
in  order  to  bring 
the  roots  in  firm 
contact  with  it. 
It  is  very  impor- 
tant to  set  the 
trees  at  precisely 
the  same  height 
that  they  were 
in  the  nursery. 
After  settling, 
citrus  trees 
should  always 
stand  in  the  or- 
chard at  the  same 
height  that  they 
did  in  the  nurs- 
ery. A  citrus 
tree  planted  too 
deep  or  with  the  soil  above  the  bud  is  doomed  to 
failure. 

When  using  the  notched  planting-board  some  planters 
prefer  to  set  the  guide  pegs  for  several  rows  before  the 
holes  are  dug,  keeping  the  board  at  right  angles  to  the 


Fig.  46.  —  Breaking  a  layer  of  hardpan  by 
means  of  a  stick  of  dynamite  discharged  in 
each  tree  hole. 


PlautuHj  the  Orchard  157 

tree  row.  A  deep  furrow  is  then  plowed  half  way  between 
the  two  rows  of  pegs.  The  holes  are  then  dug  in  this 
furrow  and  after  the  trees  are  planted  the  water  may  be 
turned  into  the  furrow.  It  is  necessary  of  course  to  draw 
up  a  small  mound  of  soil  immediately  about  the  tree  to 
prevent  the  water  from  coming  in  contact  with  the  bark. 

When  balled  stock  is  planted,  it  is  customary  to  allow 
the  balls  and  sacking  to  remain.  The  strings  are  cut 
from  about  the  crown  and  the  tree  planted,  sack  and  all. 
It  is  also  advisable  to  slit  the  sack  at  the  bottom  in  order 
to  allow  irrigation  water  to  enter  more  easily.  Ordinary 
sacking  decays  in  two  months  and  the  roots  are  not 
interfered  with.  In  the  case  of  the  balls  being  composed 
of  very  stiff  adobe  soil,  especially  when  planted  in  loose 
sandy  soil,  they  should  be  soaked  in  water  and  loosened 
somewhat  before  planting.  It  is  not  advisable  to  attempt 
to  stimulate  the  trees  by  putting  fertilizer  in  the  holes. 
Fertilizer  may  injure  or  even  kill  bare-rooted  trees  unless 
it  is  very  thoroughly  incorporated  with  the  soil  before  the 
trees  are  planted. 

Bare-rooted  trees  should  be  cut  back  when  planted, 
the  cut  waxed  over,  and  an  entirely  new  head  allowed  to 
form.  Balled  trees  may  retain  short  stubs  representing 
the  main  branches  of  the  head,  and  a  few  leaves.  Sun 
protectors  are  necessary  to  prevent  sunburning  of  the 
trunk  and  should  always  be  used,  especially  in  hot  interior 
valleys.  Sun  protectors  may  be  made  out  of  old  sacking 
wrapped  around  the  trunk  or  especially  manufactured 
yucca  tree  protectors  may  be  used.  A  number  of  thick- 
nesses of  old  newspapers  wrapped  loosely  around  the 
trunk  and  tied  with  a  string  answers  very  well  and  has  the 


158 


Citrus  Fruits 


advantage  over  yucca  of  being  cheap  as  well  as  adjustable 
in  length.  Such  tree  protectors  should  be  taken  off 
once  or  twice  during  the  first  year  in  order  to  remove  the 
water-sprouts  from  the  trunk. 

After  the  tree  is  well  set  and 
thoroughly  tramped  in,  it 
should  be  watered  immediately, 
the  ground  being  thoroughly 
soaked.  In  order  to  save  time, 
orchards  are  sometimes  planted 
before  the  facilities  for  irrigat- 
ing are  completed.  In  this  case 
the  trees  must  be  "tanked"  or 
watered  from  a  tank  wagon. 
A  basin  is  excavated  about 
each  tree,  the  soil  being  drawn 
against  the  trunk  in  the  center 
to  protect  it  from  the  water. 
After  these  basins  are  filled 
once  or  twice,  the  loose  dry 
soil  is  returned  to  its  place,  in 
order  to  conserve  the  moisture, 
and  the  ground  leveled  off.  If 
well  attended  to,  tanked  trees 
grow  fully  as  well  as  those 
irrigated  in  the  ordinary  way. 
Whether  they  may  be  tanked  to  advantage  the  second 
year  will  depend  on  the  cost  of  hauling  the  water.  Usually 
the  permanent  system  of  irrigation  should  be  ready  by 
the  second  summer. 

Wherever  citrus  trees  are  planted  in  new   localities, 


Fig.  47.  —  Newly  set  tree  prop- 
erly protected  from  the  sun. 


Planting  the  Orchard  150 

where  grain  farming,  rather  than  irrigated  crops,  have 
been  the  rule,  a  sharp  lookout  must  be  kept  for  ground 
squirrels  and  gophers.  Both  of  these  pestiferous  rodents 
are  apt  to  cause  serious  injury  to  newly  planted  citrus 
trees  unless  effectually  prevented.  Detailed  directions 
for  fighting  gophers  and  ground  squirrels  are  given  in 
Chapter  XXIV. 

INTERCROPPING 

The  question  often  arises  as  to  the  advisability  of  grow- 
ing intercalary  crops  between  the  trees  in  order  to  gain 
some  revenue  from  the  land  while  waiting  for  the  trees  to 
come  into  bearing.  There  are  many  cases  where  this 
has  been  done  advantageously,  although  the  intercropped 
citrus  orchard  is  the  exception  rather  than  the  rule. 
Such  a  practice  is  permissible  only  when  the  intercrop 
does  not  interfere  with  the  best  growth  of  the  citrus  trees. 
Citrus  nursery  stock  is  often  grown  between  the  rows  of  a 
young  orchard  where  the  soil  is  sandy  and  does  not  pack 
and  bake  as  a  result  of  the  digging  and  tramping  incident 
to  balling  the  nursery  trees.  Vegetables,  such  as  toma- 
toes, potatoes,  peppers,  lima  beans,  or  black-eyed  peas, 
may  be  grown  to  advantage.  In  interior  valleys  kaffir- 
corn  and  stock-beets  make  a  satisfactory  crop  which  may 
be  used  for  hog  feed.  The  corn-stalks  are  often  con- 
venient for  wrapping  the  young  trees  in  winter.  A  strip 
of  alfalfa  down  the  middles  improves  the  soil,  especially 
when  the  hay  is  cut  and  applied  to  the  cultivated  strip  of 
land  on  either  side  of  the  tree  rows.  Such  a  strip  of 
alfalfa  should  be  reduced  in  width  from  year  to  year  and 
plowed  out  entirely  by  the  fifth  year.     Strawberries  are 


160  Citrus  Fruits 

very  injurious  to  citrus  orcliards,  especially  on  heavy  soils, 
as  they  require  such  frequent  irrigations  that  great  injury 
from  gum  disease  often  results.  In  any  event  the  young 
orchard  should  never  be  rented  to  tenant  farmers  to  get 
all  they  can  out  of  the  land  without  reference  to  the  good 
of  the  trees. 

THE    COST    OF    PLANTING 

It  is  very  difficult  to  estimate  the  cost  of  bringing  a 
citrus  orchard  to  bearing  on  account  of  the  very  great 
variation  in  existing  conditions.  Tait  ^  gives  an  average 
estimate  for  a  ten  acre  orange  orchard  in  the  Pomona 
district  which  gives  a  fair  idea  of  the  costs  for  the  first 
five  years. 

Cost    of    Planting    and    Caring    for    Ten    Acre     Orange 
Orchard  for  Five  Years 

Ten  acres  of  orange  land $1,500 

Water  right,  or  stock  in  Water  Co 1300 

Preparing  and  grading  land 200 

1000  trees  at  $1  each 1000 

Planting  trees  at  7^  cts.  each 7.5 

Irrigating  system 175 

Irrigation  and  cultivation,  five  years 1500 

Taxes  and  incidentals,  five  years 2.50 

Fertilizer,  three  years 2.50 

Total  for  10  acres,  5  years $6250 

Since  1911  the  cost  of  some  items  has  increased,  espe- 
cially clearing  and  grading,  as  the  land  still  available  in 
this  district  is  often  encumbered  with  bowlders  and  brush. 
The  cost  of  water  has  also  increased.      See  page  359. 

1  C.  E.  Tait  —  "  U.  S.  D.  A.,  Office  of  Exp.  Stations,"  Bull. 
236,  1911. 


Planting  the  Orchard 


161 


Cost  of  New   Planting,  1911,  by  San  Diego  Fruit  Co. 


Orchard 
No.— 

Acres 

Num- 
ber OF 
Trees 

Cosx 

Sur- 
vey 

Water 

Labor 

Fer- 
tilizer 

Total 

9    .     .     .     . 

21 

158 

$126.05 

$5.00 

$8.75 

$16.21 

$5.62 

$161.63 

31    . 

2i 

237 

177.60 

5.00 

8.75 

34.21 

9.37 

234.93 

32    . 

4J 

351 

278.25 

10.00 

15.75 

58.90 

13.12 

376.02 

33    . 

6 

491 

370.72 

35.00 

21.00 

133.57 

18.75 

579.04 

78    . 

9 

712 

580.31 

12.50 

31.50 

207.63 

26.25 

858.19 

80    . 

15 

1,072 

953.91 

19.00 

52.50 

346.18 

39.46 

1,411.05 

83    . 

S 

591 

443.25 

5.00 

28.00 

149.88 

22.50 

648.63 

85    . 

4 

262 

209.00 

2.50 

14.00 

52.44 

9.84 

288.38 

106    . 

1^ 

103 

77.25 



5.25 

11.64 

3.75 

97.89 

108    . 

10 

770 

630.50 



13.50 

259.67 

29.06 

932.73 

Ill    . 

13 

1,199 

910.21 

25.50 

45.50 

301.38 

45.00 

1,327.59 

Total 

76 

5,946 

4,757.65 

119.50 

244.50 

1,571.71 

222.72 

6,916.08 

Average  cost  of  planting  per  acre $91 

Add  grading  and  preparing  land 35 

Total 126 


This  will  vary  as  the  number  of  trees  vary.  This 
report  shows  average  of  78  trees  per  acre.  Frequently 
there  are  90  trees  planted  per  acre :     ' 

First  year's  care         $38.50 

Second  year's  care 42.50 

Third  year's  care        57.50 

Fourth  year's  care 95.00 

Fifth  year's  care 115.00 

348.50 
126.00 
474.50 

In  the  case  of  Navel  oranges,  the  orchard  should 
yield  a  scattering  of  fruit  the  third  year  and  a  consider- 
able amount  the  fourth  and  fifth  years.  Valencia 
oranges  are  later  in  coming  into  bearing. 

'  Speech  of  Senator  J.  D.  Works,  "  Congressional  Record," 
July  24,  1913. 

M 


162 


Citrus  Fruits 


Statement  No.   1 

Cost  of  bringing  163  acres  of  lemon  grove  into  hearing,  trees  planted 
in  1905  by  the  Riverside  Trust  Co.  {Ltd.)  ' 

Year  ended  Sept.  30,  1905  : 

Land  and  water,  103  acres,  at  $450  per  acre  $73,350.00 

Plowing  and  leveling $1,017.36 

Fluming 4,310.31 

12,()()8  trees,  at  $1 12,()()8.00 

Planting 957.04 

Cultivation  and  irrigation       .     .     .  107.53 

Fertilizing 71.40 

Water  dues 87.17 

Total        19,158.81 

Management 113.80 

19,272.61 

Year  ended  Sept.  30,  1906  : 

Cultivation  and  irrigation       .     .     .  1,238.72 

Fertilizing         1,361.79 

Water  dues 804.65 

Taxes 369.92 

Other  expenses 953.75 

Total        4,728.83 

Management 788.03 

5,516.86 
Year  ended  Sept.  30,  1907  : 

Cultivation  and  irrigation      .     .     .  1,548.05 

Fertilizing '    .     .  734.64 

Water  dues 1,036.41 

Taxes 794.40 

Other  expenses 536.78 

Total        4,650.28 

Management 1,777.29 

6,427.57 

Carrv  forward  ....    $104,567.04 


J.  D.  Works,  loc.  cit. 


Plant'uuj  the  Orchard  1G3 

Brought  forward     .     .     .       $104,567.04 
Year  ended  Sept.  30,  1908  : 

Cultivation  and  irrigation       .     .     .       $1,967.99 

Pruning 205.15 

Fertilizing 2,522.25 

Water  dues 978.00 

Taxes 773.51 

Other  expenses 309.42 

Total        6,756.32 

Management 1,670.91 

8,427.23 
Year  ended  Sept.  30,  1909  : 

Cultivation  and  irrigation       .     .     .         2,493.20 

Pruning  lemons 125.35 

Fumigation  (90  acres) 1,423.19 

Fertilizing 411.18 

Water  dues 1,556.70 

Taxes 1,042.52 

Other  expenses 509.55 

Total        7,561.69 

.  Management 2,521.43 

10,083.12 

Total $123,077.39 

Less  crop  returns  1908       ....         1,069.50 
Less  crop  returns  1909       ....         4,431.06 

5,500.56 

Total $117,576.83 

Average,  $721.33  per  acre. 

These  figures  should  be  considered  in  connection  with 
those  given  on  pages  300  to  362.  These  tables  present 
typical  actual  expense  accounts  while  the  figures  given  in 
Chapter  XX  represent  the  averages  of  very  large  luunbers 
of  ranches  or  packing-houses  as  the  case  may  be.  The 
consideration  of  averages  alone  often  leads  to  incorrect 
conclusions,  particularly  with  agricultural  operations  where 
the  personal  factor  enters  so  largely  into  the  account. 


lG-4  Citrm  Fruits 

Statement  No.  2 

Cost  of  163  acres  of  lemon  groves,  by  the  Riverside  Fruit  Co.  (Ltd.) 

Cost  of  land  and  water,  at  $450  per  acre       .     .     .       $73,350.00 
First  year : 

Proportion  Of  cost  of  equipment,  building,  stock, 

tools,  machinery,  etc.,  at  $82  per  acre    .     .     .         13,366.00 

Cost  of  planting,  care,  etc 19,272.61 

Second  year,  cost  of  care,  etc 5,516.86 

Third  year,  cost  of  care,  etc 6,427.57 

Fourth  year,  cost  of  care,  etc 8,427.23 

Fifth  year,  cost  of  care,  etc 10,083.12 

Total 136,443.39 

Less : 

Crop  returns,  fourth  year  ....  $1,069. .50 
Crop  returns,  fifth  year        ....       4,431.06 

5,500.56 

Total $130,942.83 

Average,  $803.33  per  acre. 

Statement  No.  3 

Cost  as  per  statement  No.  2 $130,942.83 

Interest  at  6  per  cent  per  annum : 

Five  years  on  $86,716 $26,014.80 

Four  and  one-half  years  on  $19,272.61  5,203.60 
Three  and  one-half  years  on  $5,516.86  1,158.50 
Two  and  one-half  years  on  $6,427.57  964.10 

One  and  one-half  years  on  $7,357.73  662.20 

Six  months  on  $5,652.06      ....  169.56 

34,172.76 

Total 165,115.59 

Average,  $1,012.96  per  acre. 


CHAPTER   XI 

CULTIVATION,   FERTILIZATION,   AND   COVER- 
CROPS 

The  operations  incident  to  tli€  care  and  management 
of  orchard  soils  constitute  a  very  important  part  of  the 
work  of  producing  citrus  fruits.  Upon  the  inteUigence 
used  in  the  handhng  of  the  soil  will  depend  to  a  large 
extent  the  degree  of  success  finally  achieved. 

Tilling  the  soil  (1)  improves  its  physical  condition  by 
loosening  it  and  extending  the  rooting  area ;  (2)  aids  in 
saving  moisture  by  enlarging  the  water-holding  capacity 
and  by  checking  surface  evaporation ;  (3)  augments 
chemical  action  by  making  inert  plant  food  available ; 
and  (4)  admits  air  to  the  soil.  This  last  function  of  tillage 
is  very  important  because  plant  roots  must  have  air  in 
order  to  grow,  and  air  in  considerable  quantities  is  also 
essential  for  the  life  of  all  the  beneficial  bacteria  upon 
which  we  depend  for  the  making  available  of  inert  plant 
food  in  the  soil  and  for  the  acquisition  of  nitrogen  from 
the  atmosphere. 

PLOWING 

The  tillage  of  citrus  orchards  consists  of  two  kinds  of 
operations  known  as  plowing  and  cultivating.     The  land, 
165 


166 


Citrus  Fruits 


in  most  cases,  should  be  plowed  thoroughly  once  a  year, 
preferably  in  March  or  April,  which  is  the  time  the  winter 
cover-crop  is  turned  under. 

This  plowing  should  be  completed  before  the  trees  come 
into  full  bloom,  as  the  unavoidable  cutting  of  many  roots 
at  such  a  time  is  apt  to  interfere  with  the  setting  of  the 
fruit.  A  mold-board  plow  is  usually  the  best  tool,  and 
for  plowing  close  up  under  the  branches  a  special  plow  with 


Fig.  48.  —  Cultivating  newly  set  orange  trees  with  eight  chisel  cultivator. 


one  handle  is  very  convenient.  The  disk  plow  is  very 
satisfactory  in  some  soils  and  especially  in  orchards  of 
small  trees.  The  proper  depth  to  plow  is  usually  about 
eight  or  nine  inches.  It  is  unwise  to  plow  at  the  same 
depth  every  year,  for  this  is  apt  to  encourage  the  forma- 
tion of  what  is  known  as  a  plow-sole  or  hard  layer  which 
in  time  becomes  impenetrable  to  water  and  air.  Such  a 
plow-sole  may  be  largely  avoided  by  plowing  seven  inches 
deep  one  year  and  nine  or  ten  inches  the  next.  Plow-sole 
once  established  may  be  broken  up  by  running  a  subsoil 


Cultivation,  Fertilization,  and  Cover-Crops 


167 


plow  fifteen  inches  deep,  once  down  the  center  of  the 
middles  between  the  tree  rows  and  again  at  right  angles. 
Such  treatment  will  cut  a  good  many  roots  of  course,  but 
only  those  which  extend  beyond  their  legitimate  feeding 


^i^i-^^^P^^^fiM'^:p^< 


Fig.  49.  —  Cloddy  condition  due  to  land  being  worlced  while  too  wet. 


ground.     Such  subsoiling  should  be  followed  immediately 
by  copious  irrigation. 

When  the  cover-crop  is  tall,  a  heavy  iron  chain  sus- 
pended between  plow  beam  and  single-tree  will  serve  to 


1G8  Citrus  Fruits 

hold  the  mass  of  vegetation  down  until  caught  by  the  soil 
and  a  much  more  satisfactory  covering  of  the  crop  will 
result.  The  disk  harrow  should  follow  the  plow,  crushing 
down  the  loose  soil  and  bringing  it  into  close  contact  with 
the  mass  of  green  vegetation.  This  will  result  in  a  more 
uniform  incorporation  of  the  crop  with  the  soil.  In  Cali- 
fornia there  need  be  no  fear  of  souring  the  soil  by  turning 
under  a  rank,  green  crop,  for  the  large  amount  of  lime 
present  in  the  soil  quickly  neutralizes  any  acid  which 
may  form. 

Plowing  cannot  be  carried  on  as  rapidly  as  cultivation 
and  it  is  often  very  difficult  to  complete  the  spring  plow- 
ing before  the  land  gets  too  hard  and  dry  to  plow  with- 
out much  extra  labor  and  the  turning  up  of  tremendous 
clods  which  are  a  nuisance  the  rest  of  the  season.  In 
such  cases  it  is  a  good  plan  to  run  over  the  entire  acreage 
first  with  a  disk  harrow,  going  in  both  directions,  chopping 
up  the  cover-crop,  and  creating  a  light  mulch  on  the  sur- 
face which  will  retard  evaporation  and  hold  the  land  in 
good  condition  to  plow  for  a  longer  time.  By  the  use  of 
the  orchard  tractor  also  a  larger  area  of  land  may  be 
plowed  in  a  given  time. 

In  order  to  keep  the  ground  level  it  is  necessary  to  plow 
toward  the  trees  one  year  and  away  from  them  the  next. 

CULTIVATION 

Citrus  trees  are  grown  on  irrigated  lands,  and  as  irriga- 
tion and  cultivation  go  together,  it  follows  that  upon 
proper  cultivation  depends  much  of  the  success  of  the 
orchard.     If  water  is  applied  and  the  land  left  without 


Cultivation,  Fertilization,  and  Cover-Crops 


169 


cultivation,  the  surface  soil  bakes  hard,  cracks  open,  the 
moisture  escapes,  and  the  trees  suffer.  It  is  the  custom 
to  cultivate  after  each  irrigation  just  as  soon  as  the 
ground  is  dry  enough  to  stir  without  puddHng.  The 
irrigation  furrows  are  obliterated  by  the  cultivator  and 


Fi(i.  oU.  —  Ground  luider  trees  may  be  worked  with  ease  by  means  of 
an  orchard  tractor. 


the  surface  four  inches  thoroughly  stirred.  In  many 
cases  it  is  advisable  to  follow  the  first  cultivation  with  a 
second  at  the  end  of  two  weeks.  In  the  case  of  square 
plantings  the  second  cultivation  should  be  carried  on  at 
right  angles  to  the  first.  Cultivation  should  be  deeper 
on  heavy  than  on  light  soils  for  the  reason  that  it  requires 


170  Citrus  Fruits 

a  somewhat  thicker  mulch  to  prevent  the  loss  of  moisture 
from  heavy  soils.  In  the  event  that  the  weather  is  very 
hot  and  dry  immediately  after  cultivation  it  may  not  be 
necessary  to  cultivate  again  before  the  next  irrigation, 
for  the  reason  that  the  mulch  is  more  effective  when  very 
dry.  When  cultivation  is  followed  by  a  period  of  cool, 
foggy  weather,  the  capillary  connections  may  be  re-formed 
and  much  loss  of  moisture  result  unless  a  second  cultiva- 
tion be  given.  The  object  of  cultivation  is  to  create  and 
maintain  an  effecti\'e  soil  mulch  and  the  soil  stirring  process 
should  be  carried  just  far  enough  to  achieve  this  object. 
Cultivation  is  an  expensive  operation  and  much  money 
is  wasted  by  the  system  of  continuous  stirring  of  the  soil 
as  practiced  by  some  growers. 

Disk  cultivators  are  satisfactory  in  adobe  and  silt  soils 
and  especially  among  small  trees,  but  it  is  not  well  to 
depend  upon  disk  implements  exclusively.  An  occasional 
cultivation  with  narrow  chisel  teeth  will  bring  about 
better  aeration  and  prevent  the  soil  from  packing. 

All  tillage  implements  used  in  citrus  orchards  should 
be  provided  with  carefully  made  shields  which  protect 
the  low  hanging  fruit  and  prevent  it  from  being  knocked 
and  scarred  by  striking  sharp  projections  of  the  imple- 
ments as  they  pass  close  under  the  branches. 

Orchard  soils  may  be  very  seriously  injured  by  culti- 
vation at  the  wrong  time,  that  is,  when  too  wet  or  too  dry. 
Immediately  after  irrigation  there  is  a  period  of  variable 
length  when  the  soil  is  too  wet  to  stir.  If  cultivated  when 
too  wet,  the  physical  condition  will  be  ruined.  Soil  is  too 
wet  to  cultivate  when  it  is  muddy  or  scours  off  the  plow 
with  a  slick,  wet  appearance.     An  adobe  soil  is  injured 


Cultivation,  Fertilization,  and  Cover-Crops 


171 


more  than  a  sandy  soil  by  stirring  when  too  wet.  It  may 
take  a  year  or  more  to  restore  the  physical  condition 
ruined  by  injudicious  cultivation.  Ordinary  or  medium 
soils  should  be  ready  to  cultivate  about  five  or  six  days 


^■■1 

mmm. 

iPi.iXil^-sfe 

.  p  i  i  'f 

-^^^nr^ttttStfiiiai. 

Fig.  51.  —  Orchard    tractor   doing   the   work    of    eight   niulL 
desert  valley. 


hot 


after  irrigation,  and  they  remain  in  good  condition  for 
about  a  week,  after  which  they  become  too  dry.  If  not 
stirred  at  the  right  time,  the  soil  will  bake  hard  and  be 
very  difficult  to  handle.  If  extra  mules  are  then  put  on 
the  cultivator,  the  soil  will  be  turned  up  in  large  clods 


172  Citrus  Fruits 

which  will  bake  into  brick-like  musses  which  will  be  in 
the  way  for  a  year  or  more. 

It  is  often  very  difficult  to  cultivate  the  entire  acreage 
at  the  proper  time  on  account  of  the  lack  of  men  and 
teams.  In  too  many  cases  one-fourth  the  ground  is 
stirred  while  too  wet,  one-half  when  the  soil  is  just  right, 
and  one-fourth  after  the  soil  has  become  too  dry.  The 
remedy  for  this  is  to  either  increase  the  equipment  of  men 
and  mules  or  to  have  recourse  to  the  orchard  tractor, 
which  makes  it  possible  to  cover  a  much  larger  area  in 
the  same  time.  This  difficulty  is  not  serious  with  those 
growers  who  irrigate  from  local  wells.  They  are  in  a  posi- 
tion to  irrigate  a  small  piece  of  land  at  a  time  and  follow 
the  irrigation  with  cidtivation  after  the  proper  interval. 

In  old  bearing  orchards  the  trees  cover  most  of  the 
ground  and  hardly  more  than  a  strip  in  the  middles  in 
each  direction  can  be  cultivated  with  teams  or  tractors. 
It  then  becomes  necessary  to  do  a  considerable  amount  of 
hand  work.  The  ground  under  the  trees  should  be 
thoroughly  worked  over  once  a  year,  preferably  in  the 
spring  just  after  the  winter  rains  are  over.  Either  a  light 
spading  fork  or  a  short-handled  mattock  may  be  used. 
Workmen  should  be  cautioned  not  to  strike  the  trunks  of 
the  trees  or  the  crown  roots,  as  wounds  made  in  this  way 
are  very  apt  to  become  infected  with  brown-rot  gum- 
disease.  The  irrigating  furrow  nearest  the  trunk  should 
pass  just  beneath  the  outer  branches  and  the  soil  imme- 
diately about  the  trunk  will  not  be  wet  during  summer  — 
hence  the  necessity  of  hand  hoeing  to  furnish  a  mulch 
and  prevent  the  soil  about  the  crown  from  baking  as  hard 
as  a  pavement. 


Cultivation,  Fertilization,  and  Cover-Crops         173 


MULCHING 

Tlie  great  difficulty  of  handling  heavy  and  intractable 
adobe  soils  or  soils  which  acquire  an  adamantine  hardness 
when  dry  has  led  some  growers  to  substitute  a  mulch  of 
straw  or  other  humus  forming  material,  for  the  soil 
mulch,  and  discontinue  cultivation  of  the  middles  with 


II  orchard  tractor  of  the  caterpilhir  type. 


teams.  Permanent  basins  are  made  around  each  tree  of 
a  diameter  approximating  the  extreme  spread  of  the 
branches.  One  permanent  irrigating  furrow  extends  down 
either  side  of  the  tree  row  and  connects  with  each  basin. 
A  permanent  strip  of  alfalfa  occupies  all  of  the  available 
space  of  the  middle.  The  alfalfa  is  mowed  five  or  six 
times  each  season  and  thrown  into  the  basin  under  the 
trees  before  it  is  dry  enough  to  shatter.     This  material 


174  Citrus  Fruits 

accumulates  during  summer  and,  after  acting  as  an  effec- 
tive mulch,  rots  down  during  the  winter  rains  and  may  be 
worked  into  the  soil  with  hand  hoes  each  spring  before 
the  new  crop  of  mulching  material  is  available.  The 
alfalfa  is  sown  broadcast  and  is  irrigated  by  flooding  be- 
tween slight  ridges  which  bound  the  strip.  In  California 
this  system  is  still  in  the  experimental  stage,  although 
modifications  of  it  have  long  been  used  in  other  countries. 

ORCHARD    TRACTORS 

The  availability  in  California  of  large  quantities  of 
cheap  fuel  oils  has  made  possible  a  great  increase  in  the 
use  of  orchard  tractors.  There  are  a  number  of  these 
machines  now  on  the  market,  some  of  which  have  proven 
economical  and  satisfactory.  While  the  mule  is  by  far 
the  most  flexible  motor  for  small  jobs  and  for  work  on 
broken  ground  such  as  contour  plantings,  the  tractor  is 
gradually  displacing  the  mule  on  large  tracts  of  level  land. 
A  grower  who  keeps  sixteen  head  of  mules  worth  $2400 
may  retain  four  for  light  work  and  with  the  money  from 
the  sale  of  the  others  get  a  machine  which  will  do  the 
w^ork  of  the  original  sixteen.  The  engineering  of  such  a 
machine  appeals  much  more  strongly  to  the  average  farm 
boy  than  hitching,  unhitching,  and  feeding  the  mules 
morning,  noon,  and  night !  The  tractor  also  is  immune 
to  the  high  heat  of  the  interior  valleys,  which  is  often 
embarrassing  to  work-stock.  With  a  tractor  it  is  possible 
to  till  a  larger  proportion  of  the  orchard  area  at  the  right 
time. 

The  work  in  citrus  orchards  demands   a   low  down, 


Cultivation,  Fertilization,  and  Cover-Crops        175 

light,  short-turning  gas  tractor  either  of  the  three  wheel 
or  caterpillar  type.  The  machine  should  not  exceed  five 
feet  in  height  and  should  be  provided  with  steel  hood  or 
limb  protector.  Extra  strong  tillage  implements  must  be 
used  with  tractors,  as  otherwise  serious  breakage  may 
result  when  stones  or  stumps  are  struck.  An  ordinarily 
good  orchard  tractor  should  plow  about  twelve  acres  of 
orchard  a  day  at  a  cost,  including  an  ample  allowance  for 
interest  and  depreciation,  of  not  over  $12. 

FERTILIZATION 

Perhaps  no  subject  connected  with  citrus  fruit  culture 
is  hedged  about  with  as  much  uncertainty  as  that  of  fer- 
tilization of  the  soil.  California  soils  are  usually  very 
rich  in  available  plant-food,  and  in  many  cases  fertiliza- 
tion is  not  needed  for  the  first  few  years.  The  average 
orchard,  however,  will  begin  to  fail  after  five  or  six  years 
of  production  unless  fertilization  of  the  soil  is  resorted  to. 
How  much  and  what  kinds  of  fertilizer  to  apply  are  ques- 
tions which  are  extremely  difficult  to  answer  specifically, 
and  it  is  usually  necessary  for  each  grower  to  experiment 
on  his  own  land  in  order  to  gain  an  idea  of  the  best  course 
to  follow  in  his  particular  case.  No  one  should  be  dis- 
appointed if  results  fail  to  appear  quickly,  for  with  citrus 
trees  on  rich  land  it  often  requires  a  number  of  years 
before  any  measurable  differences  due  to  experimental 
fertilization  can  be  observed. 

There  is  a  very  widespread  idea  among  persons  not  well 
grounded  in  the  principles  of  agriculture,  that  the  logical 
procedure  is  to  take  samples  of  the  soil  to  a  chemist  for 


176 


Citrus  Fruits 


analysis,  and  to  lay  out  a  well  calculated  program  accord- 
ing to  his  report.  Such  a  course  is  not  often  practicable, 
however,  for  the  reason  that  while  the  chemist  may  show 
the  exact  amount  of  plant-food  in  the  soil,  he  has  as  yet 
no  way  of  measuring  the  amount  of  plant-food  which 
trees  on  a  given  soil  may  be  capable  of  taking  up.     And 


Fig.  53.  —  Substituting  baled   lima   bean    straw  for  manure  in  lemon 
orchard  near  Whittier,  California. 


there  are  still  other  difficulties,  such  as  the  trouble  ex- 
perienced in  obtaining  a  sample  which  fairly  represents  a 
considerable  area  of  land,  and  the  variation  in  the  com- 
position and  physical  make-up  of  the  soil  on  the  same 
farm  and  often  in  the  same  field.  Of  course  chemical 
analyses  are  valuable  guides  in  the  case  of  unusual  soils, 
as  when  alkali  is  suspected  or  when  some  one  of  the  neces- 
sary elements  is  markedlv  deficient.     But  the  claims  of 


Cultivation,  Fertilization,  and  Cover-Crops 


177 


some  people,  that  the  proper  formula  should  be  made  up 
by  adding  a  little  of  "  this"  to  make  the  fruit  set,  and  a 
little  of  "  that"  to  increase  the  sugar  content,  and  a  little 
of  "the  other"  to  improve  the  color,  are  very  largely 
without  foundation  of  scientific  evidence. 

A  ton  of  fresh  oranges  and  lemons  removes  the  follow- 
ing amounts  of  plant-food  from  the  soil : 


Phosphoric 
Acid 


Oranges 
Lemons 


3.88  lb. 
3.04  lb. 


1.06  lb. 
1.16  lb. 


4.22  lb. 
5.08  lb. 


Citrus  growers,  as  a  rule,  do  not  limit  themselves  to 
replacing  the  amount  of  plant-food  removed  from  the 
land,  but  commonly  apply  as  fertilizer  many  times  this 
amount  of  plant-food. 

A  study  of  soil  analyses  teaches  us  that  when  the 
average  California  soil  begins  to  fail  from  heavy  produc- 
tion nitrogen  is  most  likely  to  be  the  first  crop  limiter 
and  after  nitrogen  phosphoric  acid,  and  after  that  potash. 
Most  important  of  all,  however,  is  the  physical  condition 
of  the  soil,  for  all  of  these  elements  may  be  present  in 
excessive  amounts ;  and  yet  if  the  physical  condition  of 
the  soil  is  not  favorable  to  a  vigorous  and  healthy  root 
action,  the  plant-food  present  cannot  be  used.  By  proper 
physical  condition  is  meant  that  state  in  which  the  soil 
will  absorb  water  quickly  and  hold  it  long  as  well  as  admit 
air  to  considerable  depths. 


178 


Citrus  Fruits 


A  Type  of  Fertilization  Practice  in  Southern  California 
FOR  Old  Bearing  Trees  which  are  Too  Close  to  Permit 
Cover-crop 


Kind  op 

Fertilizer 


Lb.  per 
Tree 


How  Applied 


Date  of 
Application 


Navels 

Lemons 

Tangerines 

Navels 

Lemons 

Tangerines 

Navels 
Lemons 
Tangerines 

Navels 

Lemons 

Tangerines 


Bone  meal 
Bone  meal 
Bone  meal 

Sodium  nitrate 
Sodium  nitrate 
Sodium  nitrate 

Tankage 
Tankage 
Tankage 

Stable  manure 
Stable  manure 
Stable  manure 

Same  as  for 
1912 


2 
2 
2 

12 
12 
15 

5  eu.  ft. 
5  cu.  ft. 
5  cu.  ft. 


Drilled  in 
Drilled  in 
Drilled  in 

Hand  spread 
Hand  spread 
Hand  spread 

Drilled  in 
Drilled  in 
Drilled  in 

Disked  in 
Disked  in 
Disked  in 


Oct.,  1912 

2.5%  N 
22%  P2O5 

Mch.,  1913 
Buds  just 
starting 

Apr.,  1913 

8.35%  N 
7.65%  P2O5 

Aug.,  1913 


Oct.,  1913 


HUMUS 

Humus  is  a  dark  colored  highly  complex  organic  com- 
pound which  is  formed  by  the  decay  of  vegetable  matter 
in  the  soil.  Humus  is  present  in  relatively  small  amounts 
in  California  soils,  because  on  account  of  their  greater 
ventilation  and  higher  temperatures  the  humus  is  oxidized 
or  burned  out  of  the  soil  more  rapidly  and  does  not  accu- 
mulate to  the  extent  it  does  in  the  soils  of  humid  and 
cold  climates.  The  chief  reason  why  humus  is  so  im- 
portant is  found  in  the  fact  that  it  is  relatively  insoluble 


Cultivation,  Fertilization,  and  Cover-Crops         179 

under  good  field  conditions  and  does  not  leach  away,  but 
remains  to  form  the  food  of  nitrogen-forming  bacteria 
which  convert  it  by  degrees  into  nitric  acid,  which,  while 
one  of  their  waste  products,  yet  is  the  essential  form  of 
nitrogen  for  the  food  of  citrus  trees.  Humus  also  has 
tremendous  water-holding  capacity  and  its  presence  en- 
ables the  soil  to  take  up  water  like  a  sponge.  Humus  has 
the  tendency  to  make  close  compact  soils  more  open  and 
porous,  and  at  the  same  time  sandy  soils  are  made  more 
retentive  of  water. 

It  happens  also  that  the  average  humus  of  arid  soils 
contains  about  three  times  as  much  nitrogen  as  that  of 
humid  soils,  and  therefore  it  is  especially  important  to 
maintain  the  humous  content  of  arid  soils.  On  account  of 
the  fact  that  the  humus  in  California  soils  is  so  intimately 
associated  with  nitrogen  formation,  we  are  warranted  in 
saying  that  where  the  humus  and  moisture  conditions  of 
a  soil  are  kept  at  the  optimum,  the  question  of  nitrogen 
fertilization  becomes  of  less  importance,  especially  where 
heavy  crops  of  leguminous  green  manure  are  practicable. 

The  humous  content  of  soils  may  be  kept  high  by  the 
application  of  vegetable  matter  in  various  forms.  Stable 
manure,  bean  straw,  alfalfa  hay,  trash  and  sweepings  of 
many  sorts,  leaves,  kelp,  cover-crops,  weeds,  prunings, 
citrus  fruit  culls  —  all  these  are  used  to  supply  decaying 
organic  matter  to  the  soil.  When  the  humus  is  too  low, 
the  soil,  if  sandy,  loses  w^ater  too  rapidly ;  if  heavy,  it 
becomes  cloddy,  dead,  inert,  and  bakes  quickly  after  irri- 
gation. Such  a  soil  is  hard  to  cultivate,  forms  a  plow- 
sole  quickly,  and  it  becomes  more  and  more  difficult  to 
get  the  water  to  sink  in  rapidly.     The  trees  make  small 


180 


Citrus'  Fruits 


growth,  and  as  the  tops  become  thin,  numerous  water 
sprouts  push  out  from  the  trunk.  The  fruit  is  small 
and  appears  to  be  more  susceptible  to  splitting  and  sun- 
burn. Too  much  humus  (a  condition  very  rare  in  arid 
countries)  causes  too  great  a  vegetative  growth  at  the 
expense  of  fruit  wood,  while  the  fruit  tends  to  grow  large, 


Fig.  54.  — Cull  <,r 


coarse,  thick-skinned,  and  poor  flavored.  The  optimum 
amount  of  humus  for  citrus  trees  in  California  has  not 
been  determined  with  any  degree  of  certainty.  No  doubt 
it  varies  with  the  distance  from  the  coast,  being  higher  in 
the  hot,  interior  valleys.  It  is  suggested  that  manure,  or 
its  equivalent  in  other  vegetable  matter,  to  the  depth  of 
two  inches  over  the  entire  surface  of  the  land  once  a  year 


Cultivation,  Fertilization,  and  Cover-Cro,ps         181 

would  not  be  too  heavy  an  ai)i)lioation  on  the  type  of 
soils  common  around  Redlands  and  Riverside,  although 
somewhat  smaller  amounts  should  answer  for  soils  nearer 
the  coast. 

As  a  matter  of  practice  it  is  very  difficult  to  secure 
anything  like  adequate  supplies  of  humus-forming  ma- 
terials. Although  enormous  amounts  of  manure  are 
bought  at  high  prices  in  the  cities  and  shipped  to  the 
citrus  ranches  by  rail,  only  a  small  percentage  of  the 
orchards  are  manured  every  year.  In  order  to  make  up 
the  deficiency,  the  growing  of  green  manure  crops  has 
been  largely  resorted  to. 

GREEN    MANURE    CROPS    OR   COVER-CROPS 

Cover-crops  in  the  citrus  orchard  have  many  ad- 
vantages and  few  disadvantages. 

Advantages  — 

1.  They  increase  the  fertility  of  soil  by  the  addition  of 
humus  which  acts  as  a  Hberator  of  mineral  nutrients ; 

2.  Increase  the  water-holding  capacity  ; 

3.  ]\Iake  the  land  easier  to  work  by  improving  physi- 
cal condition ; 

4.  Encourage  an  increase  in  number  of  soil  bacteria; 

5.  Add  nitrogen  directly  to  the  soil  from  the  air  when 
such  crops  are  leguminous ; 

6.  Puncture  the  plow-sole  with  roots  which  decay  and 
leave  openings  for  the  admission  of  air  and  water ; 

7.  Bring  plant-food  up  from  below  and  leave  it  near 
the  surface ; 


182  Citrus  Fruits 

8.  Prevent  excessive  erosion  on  steep  hillsides ; 

9.  May  decrease  the  amount  of  brown-rot. 

Disadvantages  — 

1.  They  may  necessitate  irrigation  at  times  not  good 
for  citrus  trees. 

2.  Heavy  root-pruning  of  trees  incident  to  turning 
under  cover-crop  is  not  advisable  while  trees  are  blooming 
and  setting  fruit. 

3.  They  may  increase  cottony-mold  in  case  the  cover- 
crop  used  is  a  host  for  this  fungus. 

A  large  number  of  different  crops  have  been  experi- 
mented with,  but  the  ideal  plant  for  this  purpose  has  not 
yet  been  found.  Some  of  the  plants  in  use  are,  in  the 
order  of  their  importance,  common  vetch,  Canada  field 
peas,  bur  clover,  fenugreek,  hairy  vetch,  sour  clover, 
alfalfa,  buckwheat,  and  cowpeas;  the  last  named  crop 
being  grown  only  in  summer. 

Common  vetch,  J^icia  saliva,  is  by  far  the  most  com- 
monly grown  crop.  It  has  large  seeds  which  germinate 
well,  and  grows  throughout  the  winter.  It  has  the  dis- 
advantage of  maturing  rather  late  in  spring  and  is  in 
some  cases  a  host  for  the  cottony-mold  fungus.  In 
recent  years  it  has  been  seriously  injured  and  in  many 
cases  destroyed  by  a  species  of  aphid.  For  these  reasons 
the  use  of  common  vetch  is  on  the  decline. 

Recent  experiments  have  shown  that  purple  vetch, 
T'^c^a  atroimrpurea,  is  better  than  common  vetch  and  it 
is  to  be  hoped  that  an  adequate  supply  of  seed  will  soon 
be  available. 

After  an  irrigation  in  the  first  half  of  September,  the 


Cultivation,  Fertilization,  and  Cover-Crops        183 

soil  is  well  cultivated  and  fifty  to  one  hundred  pounds 
per  acre  of  vetch  seed  is  either  deeply  drilled  in  both 
directions  or  sown  broadcast,  after  which  the  irrigation 
furrows  which  are  to  remain  all  winter  are  immediately 
laid  oflP  as  close  together  as  possible. 

If  planted  in  October  or  later,  the  plants  do  not  get 
sufficiently  well  started  before  cold  weather  to  make 
much  growth  during  the  winter.  In  northern  California, 
under  irrigation,  vetch  should  be  sown  about  the  first  of 
October.  It  will  then  make  a  sufficient  growth  to  be 
turned  under  in  February  or  INIarch. 

In  the  citrus  districts  of  northern  California  vetch  is 
used  to  a  small  extent  only,  as  the  volunteer  crop  of  bur 
clover  is  often  very  satisfactory.  In  many  places  a 
common  weed,  malm,  comes  volunteer  and  growing  to  a 
height  of  three  or  four  feet  produces  a  large  tonnage  of 
green  stuff.  This  plant  is  not  a  legume,  but  makes  up  in 
quantity  what  it  lacks  in  quality.  Other  weeds  which 
sometimes  make  good  cover-crops  are  erodium,  known  as 
"filaree"  and  a  cheno podium.. 

In  southern  California  a  winter  cover-crop  of  some  kind 
is  the  rule  on  all  except  the  \'ery  stiff  adobe  soils  near 
the  coast.  Such  soils  are  injured  in  texture  by  lying 
without  cultivation  all  winter,  and  consequently  manure 
is  used  to  the  exclusion  of  a  cover-crop,  and  the  cultiva- 
tors are  kept  moving  all  winter. 

The  question  is  often  asked  whether  it  is  not  advisable 
to  inoculate  seed  to  be  sown  on  land  that  has  not  pre- 
viously grown  that  crop.  In  California,  it  has  been  found 
that  the  bacteria  necessary  to  nodule  formation  on  the 
more  common  leguminous  crops  are  present  in  most  soils. 


184  Citrn,s  Fruits 

The  first  seeding  may  not,  however,  be  as  abundantly 
inocuhited  as  desired,  and  in  some  sections  the  bacteria 
essential  to  certain  crops  seem  to  be  entirely  lacking.  In 
such  case  the  land  should  be  inoculated  by  drilling  in  with 
the  seed  a  small  quantity  of  fresh  soil  taken  from  some 
field  which  has  grown  the  ixirticular  crop  satisfactorily. 

A  few  growers  who  have  sufficient  water  grow  a  sum- 
mer crop  of  cowpeas  in  addition  to  the  winter  crop. 
This  of  course  is  advisable  where  practicable,  but  on  ac- 
count of  the  higher  price  of  summer  water  and  the  need 
of  most  soils  for  frequent  stirring,  the  practice  is  con- 
siderably limited.  In  the  northern  part  of  the  Sacra- 
mento ^  alley,  where  water  is  cheap,  the  practice  of  plant- 
ing the  orchards  permanently  to  alfalfa  is  on  the  increase. 
As  yet  this  can  only  be  regarded  as  an  experiment  and 
should  not  be  adopted  on  a  large  scale  at  the  present 
time. 

SUMMARY 

In  summing  up  this  discussion  of  soil  management  it 
may  be  said  that  optimum  production  depends  upon  a 
number  of  factors  working  together.  As  a  chain  is  only  as 
strong  as  its  weakest  link,  so  the  size  of  the  crop  cannot 
rise  above  the  one  factor  which  is  farthest  from  the 
optimum.  The  effort  of  every  grower  should  be  to  dis- 
cover the  "crop  limiter"  in  his  particular  grove.  First 
he  should  provide  plenty  of  water  to  dissolve  the  plant 
food  and  carry  it  into  the  plant.  Then  he  should  increase 
the  humous  content  to  the  point  where  his  soil  is  actually 
"alive"  with  bacteria  working  to  fix  for  him  the  free 
nitrogen  of  the  air  and  make  available  the  tremendous 


Cultivation,  Fertilization,  and  Cover-Crops         185 

stores  of  inert  plant-food  in  the  soil  minerals.  This 
should  be  done  by  the  application  of  manure  or  straw 
and  the  growing  of  leguminous  cover-crops.  The  soil 
should  be  deeply  plowed  and  cultivated  in  order  to  en- 
courage the  roots  to  go  down  after  the  plant-food  which 
in  arid  soils  is  available  at  unusual  depths.  The  arid 
soil  farmer  has  a  great  advantage  in  this  regard,  and  this 
advantage  should  not  be  thrown  away  by  shallow  irriga- 
tion and  cultivation. 

After  all  this  is  done  it  is  time  to  consider  the  kinds 
and  amounts  of  commercial  fertilizers  to  apply.  This 
will  be  found  a  puzzling  question  and  one  which  must  be 
largely  determined  by  each  individual  grower  for  him- 
self. He  should  first  experiment  by  trying  out  each 
plant-food  element  alone.  A  few  rows  should  receive 
nitrate  of  soda,  a  few  phosphoric  acid,  and  a  few  sulphate 
of  potash,  with  check  rows  receiving  nothing  alternating 
with  the  fertilized  rows.  It  will  require  a  number  of 
years'  patient  effort  perhaps  before  results  will  be  evident. 
Having  found  the  element  or  elements  to  which  his  trees 
respond,  his  next  step  is  to  determine  the  optimum 
amount  of  such  fertilizers  which  it  is  profitable  to  use  at 
the  price  he  has  to  pay  for  them. 

Meanwhile  the  grower  should  apply  to  the  remainder 
"of  his  acreage,  not  included  in  the  experiment,  a  fair 
amount  of  fertilizer  as  determined  by  the  amount  of 
nutrients  removed  in  the  crop,  modified  to  some  extent 
perhaps  by  the  former  results  and  experience  of  other 
growers  in  the  immediate  neighborhood. 

While  fertilization  is  a  very  important  part  of  the 
process  of  producing  citrus  fruits,  too  great  or  too  quick 


186  Citrus  Fruits 

results  should  not  be  expected.  A  few  extra  pounds  of 
fertilizer  should  not  be  expected  to  overcome  the  injury 
done  by  neglect  or  carelessness  in  irrigation,  cultivation, 
or  pruning.  There  is  an  old  Roman  ])r()vcrl)  which  applies 
especially  well  to  citrus  fruit  raising.  It  is  somewhat  as 
follows : 

"The  footprints  of  the  owner  make  the  best  fertilizer." 


CHAPTER   XII 

IRRIGATION 

In  all  parts  of  the  arid  Southwest  citrus  fruits  require 
irrigation.  In  many  localities  in  California,  especially 
where  the  rainfall   is   heavy,  deciduous   fruits,   such  as 


Fig.   55.  —  Canal   lined  with   cenunt.        rran- 
into  orange  gloves. 

187 


ition  of   desert  hills 


188  Citrus  Fruits 

prunes,  peaches,  walnuts,  grapes,  and  almonds,  are  grown 
very  successfully  without  irrigation.  The  very  deep  rich 
soils  not  only  encourage  deep  rooting,  but  they  constitute 
a  reservoir  for  the  winter  rainfall  which  is,  or  should  be, 
carefully  conserved  for  the  use  of  the  trees  by  frequent 
surface  cultivation  during  summer.  Citrus  fruits,  how- 
ever, being  evergreen,  transpire  large  amounts  of  water 
at  all  seasons  of  the  year;  and  while  in  the  more  favored 
locations  the  trees  may  remain  alive,  they  should  not  be 
expected  to  bear  commercial  crops  without  irrigation 
water  in  addition  to  the  rainfall. 

AMOUNT    OF    WATER    NEEDED 

The  amount  of  water  needed  will  depend  upon  the 
amount  of  rainfall,  the  character  of  the  soil,  the  climatic 
conditions,  and  the  age  and  kind  of  trees.  Heavy  clay  or 
adobe  soils  are  usually  difficult  to  saturate,  but  once  well 
soaked  they  retain  the  water  well,  and  a  less  amount  is 
needed  on  such  soils  than  on  open  gravelly  soils  through 
which  the  water  passes  more  readily.  Near  the  coast, 
where  the  air  is  moist,  trees  require  somewhat  less  water 
than  in  interior  valleys  where  it  is  more  windy  and  the  air 
is  hot  and  very  dry  in  summer.  The  draught  on  the  tree 
for  water  varies  with  four  factors  :  the  temperature,  rela- 
tive humidity,  velocity  of  wind,  and  the  amount  and  inten- 
sity of  the  sunlight.  The  observers  of  the  United  States 
Weather  Bureau  record  all  of  these  factors,  but  apparently 
no  systematic  attempt  has  been  made  to  correlate  them. 
The  porous-cup  atmometer  automatically  correlates  all 
of  these  factors,  the  record  indicating  in  cubic  centimeters 


Irrigation 


189 


of  water  evaporated  per  day,  the  total  demand  of  the  air 
on  the  plant  for  water.  The  writer  kept  dupHcate  atmom- 
eter  records  for  one  year  at  Whittier  and  Riverside, 
California,  for  the  purpose  of  measuring  this  difference 
in  the  climate  of  the  two  places.  Whittier  is  in  Los 
Angeles  County,  about  fifteen  miles  from  the  coast, 
and  situated  on  the  foothills  facing  the  sea.  Riverside  is 
about  thirty-five  miles  due  east  of  Whittier  and  on  the 
opposite  side  of  the  hills. 

Atmometeb  Records  June  1,  1911,  to  May  31,  1912 


1911,  .June 
July        . 

August 

September 

October 

November 

December 

1912,  January 
February 
March 
April 
May       .     . 


Total  .     .     . 
Average  daily 


Whittier 

Riverside 

686.0  cc. 

1,302.1  ec. 

779.1 

1,301.0 

934.8 

1,244.3 

852.7 

1,421.7 

989.7 

1,249.7 

1,-544.0 

1,541.4 

1,279.3 

1,371.3 

1,319..5 

1,211.1 

1,025.0 

1,019.8 

654.6  1 

620.4 

464.8 

1,017.9 

707.2 

1 .643.4 

11,236.7 

14,944.1 

30.7 

40.9 

Estimated  from  incomplete  records. 


These  figures  show  that  the  draught  of  the  air  for  water 
is  about  33  per  cent  greater  at  Riverside  than  at  Whit- 
tier, and  this  fact   considered   in   connection   with    the 


190 


Citrus  Fruits 


b'm.  ob.  —  Preparing  the  ground  for  furrow  irrigation. 
(From  U.  S.  D.  A.,  Farmers'  Bui.  No.  404.) 


more   porous   character  of  the   Riverside   soils  explains 
why  a  larger  quantity  of  irrigation  water  is  needed. 

Of  course  it  goes  without  saying  that  old  bearing  trees 
require  much  more  water  than  young  trees,  and  it  is  essen- 


Irrigation  191 

tial  for  permanent  success  that  the  right  to  sufficient 
water  for  old  trees  be  secured  in  the  beginning  and  jealously 
guarded  until  it  is  all  needed.  As  a  basis  for  estimating 
the  capacity  of  wells  and  streams,  the  available  flow  during 
the  driest  years  on  record  should  be  taken.  The  rainfall 
is  variable  and  it  is  not  unusual  for  several  dry  years  to 
occur  in  succession.  At  such  times  the  underground 
stores  of  water  are  greatly  depleted  and  the  trees  are  apt 
to  suffer. 

Inasmuch  as  the  average  yield  in  pounds  of  mature 
lemon  trees  is  considerably  greater  than  that  of  orange 
trees,  it  follows  that  they  require  more  water,  and  this  is 
borne  out  by  the  experience  of  the  growers. 

From  what  has  been  said  it  is  clear  that  no  definite 
rule  can  be  laid  down  as  to  the  exact  amount  of  water 
needed  under  different  conditions.  For  the  sake  of  com- 
parison, however,  it  may  be  stated  in  a  general  way  that 
water  to  a  depth  of  from  thirty-five  to  forty-five  inches, 
including  both  irrigation  and  rainfall,  should  be  allowed 
bearing  citrus  trees.  Full  bearing  orchards  on  retentive 
soils  near  the  coast  should  be  provided  with  about  one 
and  one-fourth  ordinary  miner's  inches  to  each  ten  acres, 
while  the  same  trees  in  the  hot  interior  valleys  and  es- 
pecially on  gravelly  soils  should  have  not  less  than  three 
ordinary  miner's  inches  to  ten  acres. 

The  miner's  inch  in  California  has  two  values.  The 
ordinary  one  adopted  by  custom  is  a  stream  flowing 
freely  through  an  opening  one  inch  square  under  a  pres- 
sure head  of  four  inches  on  the  center  of  the  opening. 
This  flow  is  equivalent  to  one-fiftieth  of  a  cubic  foot  per 
second  or  nine  gallons  per  minute.     The  miner's  inch  as 


192  Citrus  Fruits 

defined  by  the  statute  of  1901  and  known  as  the  "Statute 
Inch"  is  equivalent  to  a  stream  flowing  freely  through 
an  opening  one  inch  square  under  a  pressure  head  of  six 
inches  on  the  center  of  the  opening.  This  flow  is  equiva- 
lent to  one-fortieth  of  a  cubic  foot  per  second  or  eleven 
and  one-fourth  gallons  per  minute.  All  contracts  for 
water  should  specify  the  miner's  uich  to  be  used. 

SOURCES    AND    COST    OF   WATER 

Water  for  citrus  orchards  is  secured  by  diversion  from 
flowing  streams,  by  pumjjing  from  reservoirs  in  under- 
ground gravel  beds,  and  from  artesian  wells.  The  best 
water  rights  are  old  and  well  established  claims  to  stated 
quantities  of  water  from  streams  which  are  fed  the  year 
round  by  melting  snows  of  high  mountains.  The  right 
to  a  water  supply  pumped  from  wells  is  good  provided 
the  land  to  be  irrigated  overlies  the  underground  reser- 
voir, the  owner  of  such  land  having  an  equal  right  with 
other  overlying  land  owners.  In  cases  where  the  surface 
of  the  ground  immediately  over  the  reservoir  is  not  suited 
to  cultivation  the  water  may  be  transported  for  use  upon 
any  land  within  the  same  natural  drainage  area.  The 
right  to  transport  water  from,  one  natural  drainage  area 
into  another  for  irrigation  purposes  is  questionable. 

Where  a  great  many  wells  are  put  down  in  the  same 
neighborhood  they  are  apt  to  interfere  with  each  other, 
and  the  general  level  of  the  underground  water  may  be 
drawn  down  to  such  an  extent  that  the  pumps  may  have 
to  be  lowered  and  engines  of  greater  power  installed  to 
lift  the  water  to  the  surface.     Artesian  wells  often  cease 


Irrigation  193 

to  flow  under  such  conditions.  In  cases  where  a  series  of 
dry  years  brings  about  a  marked  diminution  in  the  supply 
of  the  underground  water,  the  lands  immediately  over- 
lying the  water-bearing  gravels  have  first  right  to  the 
water;  and  in  case  these  lands  are  not  cultivated,  then 
the  distant  lands  enjoy  prior  rights  in  the  order  in  which 
the  water  for  them  was  appropriated. 

The  cost  of  water  is  extremely  variable,  running  from 
almost  nothing  to  as  high  as  fifty  or  sixty  dollars  an  acre 
a  year.  With  the  development  of  cheap  electric  energy 
and  the  internal  combustion  engine,  water  may  now  be 
economically  lifted  to  great  heights.  One  large  company 
near  Corona,  by  the  use  of  what  is  known  as  a  "  boosting 
plant"  run  by  an  internal  combustion  engine,  lifts  water 
to  a  height  of  750  feet  for  the  irrigation  of  lemon  orchards. 

The  average  cost  of  water  used  in  citrus  orchards  in 
California  is  about  twenty  dollars  an  acre  a  year. 


METHODS    OF    DISTRIBUTION 

In  the  early  days  water  was  distributed  to  the  high 
places  throughout  the  orchards  through  open  ditches  and 
viaducts.  These  were  very  unsatisfactory  because  they 
filled  up  with  grass,  weeds,  and  silt  and  had  to  be  cleaned 
out  quite  often.  Not  only  was  this  expensive,  but  a 
great  deal  of  water  was  lost  by  seepage.  These  ditches 
were  replaced  by  wooden  flumes,  which  answered  well 
until  they  rotted  out.  They  have  been  gradually  replaced 
by  concrete  pipe-lines,  which  are  now  almost  universally 
used  in  the  citrus  orchards  of  California.  If  well  made 
of  one  part  of  cement  to  four  parts  of  clean,  sharp  sand 


194 


Citrus  Fruits 


this  pipe  is  permanent  and  has  proved  highly  satisfactory 
wherever  the  pressure  is  not  over  ten  feet.  It  is  laid 
about  fifteen  inches  below  the  surface  or  deep  enough  to 
be  out  of  the  way  of  the  subsoil  plow.  The  joints  are 
carefully  cemented  to  prevent  leakage  and  the  entrance 


of  roots.  Where  the  pressure  is  greater  than  ten  feet, 
steel  pipe  must  be  used.  Concrete  pipe  twelve  inches  in 
diameter  costs  about  thirt\-five  cents  a  foot,  laid. 

The  pipe-lines  are  laid  across  the  rows  and  at  the  end 
of  each  row  a  standpipe  is  placed  over  the  line  in  such  a 
way  that  the  water  will  rise  to  a  certain  height  and  over- 
flow back  into  the  line.     Each  standpipe  is  furnished  with 


Irrigation  195 

delivery  spouts  controlled  by  close-fitting  metal  gates. 
The  overflow  provides  for  an  even  pressure  on  the  delivery 
spouts  at  all  times. 

Where  the  check  system  is  used  the  water  is  delivered 
at  the  highest  corner  in  a  large  head  and  conveyed  to 
different  parts  of  the  orchard  through  temporary  earth 
ditches. 

TIME    OB^    APPLICATION 

Citrus  trees  should  never  be  allowed  to  suffer  for  water. 
Olive  trees,  aside  from  dropping  the  fruit,  are  not  per- 
manently injured,  but  citrus  trees  receive  a  setback  which 
it  often  takes  years  to  overcome.  The  soil  should  be 
watched  and  water  applied  before  the  trees  show  any 
signs  of  distress  such  as  curling  of  the  leaves  or  dropping 
of  the  fruit.  It  is  very  important  that  the  grower  keep 
in  close  personal  touch  with  the  condition  of  the  soil  to 
the  depth  of  four  or  five  feet.  The  only  way  to  find  out 
the  condition  of  the  soil  is  by  digging  holes  at  various 
places  or  by  using  the  King  soil  sampler. 

\Miere  growers  take  the  water  from  a  company  serving 
a  large  area,  they  usually  irrigate  in  rotation  about  once  a 
month  during  the  summer  and  less  often  during  the  rainy 
season.  This  system  is  objected  to  on  the  ground  that 
there  is  not  an  incentive  to  use  water  economically. 
While  the  trees  are  small  and  the  supply  of  water  is  greater 
than  necessary  there  is  a  tendency  to  try  to  make  amends 
for  poor  cultivation  by  over  irrigation. 

Experienced  growers  are  able  to  determine  when  a  soil 
needs  water  by  simply  feeling  it  in  the  hands.  Beginners, 
however,  should  make  physical  tests  of  the  water  content 


190  Citnt.s  Fruits 

occasionally.  Such  a  test  is  very  simple  and  may  be 
performed  by  any  one.  Samples  may  be  taken  to  a 
depth  of  four  feet,  keeping  the  soil  from  each  foot  separate. 
These  samples  are  weighed  immediately,  and  again  after 
having  been  exposed  to  the  hot  sun  for  the  greater  part 
of  a  day.  The  difference  in  weight  will  represent  the 
moisture  content.  It  is  considered  that  six  per  cent 
by  weight  of  free  moisture  is  sufficient,  in  sandy  loam 
soils,  to  keep  the  trees  in  good  condition. 

"  Dr.  Loughridge  in  his  experiments  at  Riverside  in 
June,  1905,  found  an  average  of  3.5  per  cent  in  the 
upper  two  feet  and  an  average  of  G.16  per  cent  below 
this  level  in  an  orchard  which  had  not  been  irrigated  since 
October  of  the  preceding  year.  It  had  received,  however, 
a  winter  rainfull  of  about  sixteen  inches.  On  examina- 
tion it  was  found  that  the  bulk  of  the  roots  lay  between 
the  first  and  fourth  foot.  These  trees  in  June  seemed 
to  be  merely  holding  their  own.  WTien  irrigated,  July  7, 
they  began  to  make  new  growth.  A  few  days  after  the 
water  was  applied,  the  percentage  of  free  water  in  the 
upper  four  feet  of  soil  rose  to  9.64  per  cent.  The  results 
of  these  tests  seemed  to  indicate  that  the  percentage  by 
weight  of  free  moisture  should  range  between  5  and 
10  per  cent  in  average  orchard  loams."  ^ 

The  temperature  of  the  water  oftentimes  has  an  im- 
portant relation  to  the  health,  and  productivity  of  the 
trees.  Hilgard  -  has  the  following  to  say  in  regard  to 
this :  "  To  those  who  are  located  in  or  near  the  foothills 
and  are  apt  to  receive  their  irrigation  water  at  a  tem- 

1  Fortier,  U.  S.  Dept.  Agr.,  Farmers'  Bui.  No.  404,  p.  24. 

2  Rpt.  Calif.  Exp.  Sta.,  1897-98,  p.  54. 


Irrigation 


19; 


Fig.  08.  —  Zigziig  furrows  wet  the  ground  between  the  trees 


198  Citrus  Fruits 

perature  not  far  above  that  at  which  it  left  the  high 
Sierras,  this  is  a  very  serious  consideration.  Many  a 
time  there  have  come  to  the  Station  complaints  of  an 
unaccountable  dropping  of  fruit,  or  injury  to  field  crops, 
which,  when  investigated,  were  directly  traceable  to  the 
use  of  cold  irrigation  water,  at  a  time  when  the  trees  and 
crops  were  in  full  growth.  As  the  same  ditch  may  at 
different  times  supply  him  warm  or  cold  water,  accord- 
ing to  the  use  made  of  it  before  it  reaches  the  lower  level, 
the  irrigator  should  use,  if  not  a  thermometer,  at  least 
his  hand  and  a  good  slice  of  common  sense,  to  determine 
whether  or  not  he  is  running  a  risk  of  injury  by  applying 
it  directly  to  his  land." 

METHODS    OF    APPLICATION 

In  orchard  irrigation  it  is  necessary  that  the  water  be 
evenly  divided  between  all  the  units  of  space  both  hori- 
zontal and  vertical.  It  is  desirable  that  the  water  be 
retained  in  the  soil  until  taken  up  by  the  roots  of  the 
trees.  Part  of  the  water  may  escape  through  leaching 
into  the  sub-drainage,  and  part  will  evaporate  from  the 
surface.  It  should  be  the  aim  of  the  irrigator  to  reduce 
the  loss  through  these  avenues  as  much  as  possible.  Sub- 
irrigation  through  some  kind  of  system  of  pipes  w^ould 
seem  to  be  ideal,  but  has  been  found  to  be  impracticable, 
on  account  of  the  plugging  of  the  openings  in  the  pipe 
by  tree  roots  in  their  natural  growth  toward  the  moisture 
in  the  undrained  pipes. 

Overhead  irrigation  is  being  experimented  with  on  a 
small  scale  by  various  growers,  and  in  some  cases  gives 


Irrigation 


199 


promise  of  success.  Mr.  David  Overholtzer  of  Covina 
is  irrigating  nine  acres  of  twenty-two-year-old  Valencia 
oranges  by  this  method  with  apparent  success.  He  lifts 
his  water  147  feet  or  more  from  a  well  in  the  orchard  with 
a  Pomona  deep  well  pump  and  a  40  H.  P.  gas  engine.  A 
centrifugal  pump  keeps  the  pressure  on  the  line  at  about 
forty  pounds.     The  supply  pipes  run  down  the  center 


Fig.    59.  —  Overhead    irrigation    ai-stoiu    in    old    orange    orchard    near 
Covina,  California. 


of  the  orchard  and  from  them  radiate  the  delivery  pipes, 
one  over  every  other  middle  at  an  elevation  of  16  feet. 
The  patent  brass  nozzles,  -jYo^  inch  diameter,  are  placed 
four  feet  apart,  and  the  streams  of  water  are  thrown 
laterally  about  twenty  feet.  The  entire  orchard  is  irri- 
gated at  once  and  the  delivery  pipes  are  all  rotated  from 
one  windlass  in  the  pump-house.  The  equivalent  of  one 
inch  of  rain  is  applied  in  about  twelve  hours. 


200  Citrus  Fruits 

The  two  chief  methods  of  application  are  by  basins 
and  furrows.  Furrows  are  best  for  heavy  soils,  but  basins 
are  often  necessary  on  sandy  or  gravelly  soils  across  which 
it  is  impracticable  to  transfer  the  water  except  in  very 
large  heads.  In  loose  sandy  soils,  water  percolates  with 
such  rapidity  near  the  head  ditch  that  a  large  part  is 
lost  by  i)assing  far  below  the  roots  and  possibly  into  sand 
and  gravel  strata,  through  which  it  flows  away.  In  one 
orchard  measured  by  Loughridge  the  water  had  per- 
colated to  a  depth  of  twenty-six  feet  at  a  distance  of 
thirty  feet  from  the  head  ditch.  As  it  is  doubtful  if 
water  at  a  depth  of  more  than  five  feet  below  the  root 
systems  will  be  of  any  benefit  to  the  trees,  it  is  evident 
that  a  large  part  of  this  water  was  wasted.  For  these 
reasons  it  is  advisable  to  use  the  basin  system  on  all  loose 
sandy  soils.  By  the  use  of  a  ridger,  the  loose  earth  is 
thrown  up  into  ridges  midway  between  the  rows  in  two 
directions  at  right  angles  to  each  other.  This  divides  up 
the  ground  into  a  number  of  squares  with  a  tree  in  the 
center  of  each.  A  ditch  is  then  run  from  the  supply  line 
at  the  head  down  every  alternate  row  by  splitting  the 
ridge  in  this  row.  The  water  is  then  admitted  in  a  head 
of  40  or  50  miner's  inches  and  run  through  to  the  lower 
two  basins.  After  these  are  full,  the  water  is  admitted 
to  the  two  above,  and  so  on  till  the  double  row  is  completed. 

By  far  the  larger  part  of  citrus  irrigation  in  California 
is  done  by  the  furrow  method.  The  orchard  is  divided 
into  sections  and  head  lines  of  concrete  pipe  with  stands 
run  across  the  orchard  from  300  to  500  feet  apart.  The 
distance  between  these  is  known  as  a  "  run."  The  length 
of  these  runs  is  governed  by  the  size  of  the  orchard  and 


Irrigation  201 

the  kind  of  soil.  Where  the  soil  is  open  and  water  suiks 
readily  through  it,  300  or  400  foot  runs  should  be  used, 
otherwise  much  water  is  lost  by  deep  percolation  on  the 
upper  part  of  the  tract.  On  very  sandy  or  gravelly  soil 
having  a  slight  slope,  the  proper  length  of  furrows  is  200 
feet,  while  on  heavier  soils  with  considerable  grade,  the 
length  may  be  increased  to  500  or  even  to  700  feet.  The 
grade  of  the  furrows  varies  widely  from  one  per  cent  or 
less  to  ten  per  cent  or  more.  The  steeper  the  grade,  the 
more  likelihood  of  washing  and  consequently  the  smaller 
the  stream  of  water  used.  On  ordinary  soils,  a  three  or 
four  per  cent  grade  is  preferred.  Where  the  grade  is 
more  than  ten  per  cent  the  furrows  should  be  run  on 
the  contour. 

The  number  of  furrows  used  between  each  tree  row 
depends  on  the  age  of  the  trees,  the  distance  between 
rows,  the  depth  of  the  furrows,  and  the  character  of  the 
soil.  During  recent  years  the  general  trend  of  orchard 
practice  is  toward  deep  rather  than  shallow  furrows,  a 
depth  of  eight  inches  being  frequently  used.  The  furrow- 
ing implement  ordinarily  used  consists. of  a  sulky  frame 
to  which  are  attached  two  or  three  wide  shovel  plows. 
Sometimes  a  subsoil  plow  is  run  in  the  bottom  of  the  middle 
furrow  and  again  at  right  angles  in  the  center  of  the 
middles  in  order  to  insure  deep  percolation  of  the  water. 

As  the  trees  groAV  and  occupy  most  of  the  space,  it  be- 
comes difficult  to  run  the  furrows  close  to  the  trees,  and 
consequently  there  is  a  large  space  left  in  the  row  between 
the  trees  which  is  not  wet.  This  trouble  is  met  by  cross- 
furrowing.  While  this  occasions  a  large  amount  of  hoe 
work  in  reopening  the  furrows  where  they  cross,   it  is 


202 


Citrus  Fruits 


absolutely  necessary  when  large  wide-spreading  trees  are 
irrigated  by  the  furrow  method.  Cross-furrowing  is  also 
used  with  newly-set  trees  when  the  cost  of  water  is  such 
as  to  require  the  most  eco- 
nomical use. 

After  the  irrigator  has 
walked  along  the  row  of 
stands  and  opened  enough 
jets  to  consume  the  head  of 
water,  one  to  each  furrow, 
he  proceeds  to  the  lower  end 
and  awaits  the  arrival  of  the 
water.  As  soon  as  two  or 
three  runs  are  through,  he 
walks  across  the  lower  end 
and  takes  note  of  the  progress 
of  the  water  in  each  furrow  by 
number.  Returning  to  the 
upper  end,  he  cuts  down  the 
flow  in  those  furrows  which 
are  "through"  and  increases 
the  flow  in  the  others.  This 
process  is  repeated  several 
times  until  just  enough  water 
is  admitted  to  each  furrow  to 
run  through  but  not  waste  at 
the  lower  end.  All  the  while 
he  must  devote  some  time  to  locating  and  plugging  gopher 
and  mole  holes,  which  are  apt  to  intercept  some  streams, 
and  to  keeping  a  watch  for  "  dams,"  which  are  accumula- 
tions of  floating  leaves  which  force  the  water  to  rise  and 


Fig.  60.  — The  King  soil  sam- 
pler is  very  useful  for  deter- 
mining the  downward  progress 
of  irrigation  water. 


Irrigation  203 

break  over  from  one  furrow  into  another,  thus  causing 
serious  trouble.  After  once  well  regulated,  the  water 
should  not  require  much  attention,  and  is  allowed  to  run 
till  the  ground  is  soaked  to  a  depth  of  four  feet  as  ascer- 
tained by  digging  or  pushing  down  the  shovel  handle. 
After  being  turned  off,  the  water  in  the  soil  will  usually 
percolate  a  foot  or  two  farther,  thus  wetting  the  required 
five  feet.  In  case  the  water  will  not  soak  down  on 
account  of  the  presence  of  a  hard  layer  such  as  plow-sole 
or  hardpan,  this  condition  should  be  remedied  at  once. 
This  may  be  done  either  by  blasting  the  soil  in  the  case  of 
hardpan  or  by  using  a  sub-soil  plow  as  described  above  in 
the  case  of  ordinary  plow-sole. 


CHAPTER   XIII 
PRUNING   AND    TOP-WORKING 

There  is  probably  no  horticultural  operation  about 
which  more  dogmatic  advice  has  been  given  than  pruning. 
Among  practical  citrus  growers  there  is  much  diversity 
of  opinion,  and  this  is  due  in  most  cases  to  the  attempt 
to  master  all  the  details  without  previously  obtaining  a 
true  conception  of  the  principles  involved. 

We  hear  little  of  the  "  Let  Nature  have  her  way  "  senti- 
ment in  these  days  of  scientific  horticulture.  While  our 
old  sweet  seedlings  may  have  developed  into  fairly  satis- 
factory trees  with  but  little  attention,  the  highly  artificial 
Eurekas  and  Navels  which  we  grow  to-day  are  difll'erent. 
They  should  no  more  be  expected  to  take  care  of  them- 
selves than  should  a  highly  bred  Jersey  cow  turned  out  on 
the  range  be  expected  to  give  her  normal  flow  of  milk. 

It  is  difficult  to  give  definite  detailed  directions  for  the 
pruning  of  citrus  trees  because  trees  are  like  children,  every 
one  difYerent  and  presenting  a  set  of  individual  problems. 

In  pruning  citrus  trees,  the  chief  object  sought  may  be 
stated  as  follows :  to  develop  such  shape  and  size  of  tree 
and  strength  of  limb  as  will  permit  the  bearing  of  optimum 
crops  of  maximum  quality  without  damage  to  the  frame- 
work of  the  tree ;  which  at  the  same  time  must  be  con- 
204 


Priming  and  Top-Working 


205 


sistent  with  convenient  and  economical  cultivation, 
fumigation,   and   harvesting. 

The  first  requirement  in  achieving  the  above  object  is 
to  head  the  tree  correctly,  and  in  the  case  of  balled  stock 
this  is  done  in  the  nursery  row. 

The  usual  height  at  which  citrus  trees  are  headed  is 
about  thirty-three  inches,  although  there  is  some  variation 


Fig.    61.  —    A    well    pruned    Eureka    lemon    orchard    photographed 
August  10th. 


from  this,  and  two  or  three  inches  higher  or  lower  will  not 
make  any  material  difference.  It  is  not  wise  to  pinch  out 
the  bud  and  head  the  tree  as  soon  as  the  shoot  reaches 
the  required  height.  It  should  be  allowed  to  grow  at  least 
six  inches  taller  and  then  cut  back  to  the  desired  height. 
This  will  result  in  harder  and  stronger  wood  at  the  top, 
where  the  main  branches  which  constitute  the  framework 
of  the  tree  are  to  grow.     This  cutting  back  will  force  into 


206 


Citrus  Fruits 


growth  a  number  of  buds  all  along  the  trunk.  Five  or  six 
of  these  should  be  selected  for  the  main  branches  and  they 
should  not  only  be  distributed  on  all  sides  but  also  over  the 
upper  thirteen  inches.  When  two  limbs  join  the  trunk 
at  the  same  height,  they  are  apt  to  split  the  trunk  under  the 
load  of  fruit  in  later  years.  Whenever  two  branches  grow 
out  from  one  bud,  one  of  them  should  always  be  removed. 
Every  shoot  which  puts  out  from  the  lower  twenty  inches 
should  be  removed.     It  is  customary  to  allow  the  big 


Fig.  62.  —  Prototype  of   California  pruning  saw. 
"  Hesperides,"  1708. 


From   Voickamer' 


broad  leaves  which  grow  on  the  main  trunk  to  remain 
until  the  trees  are  dug  for  sale.  The  main  branches  may 
grow  out  a  foot  or  so  in  length,  but  are  usually  cut  back 
to  six-inch  stubs  when  the  trees  are  dug. 

When  trees  are  dug  with  bare  roots,  the  entire  top  is 
cut  off,  leaving  the  trunk  as  a  straight  cane.  The  work 
of  heading  the  tree  must  then  be  done  in  the  orchard.  In 
some  places,  it  has  become  a  common  practice  to  make 
vertical  slits  in  the  trunks  of  young  orchard  trees  with  a 
sharp  knife.  In  some  cases,  a  V-shaped  blade  is  used 
which  lifts  out  a  small  strip  of  bark,  the  idea  being  to  re- 


Pruning  and  Top-WorJdng  207 

lease  an  imaginary  pressure  on  the  bark  and  allow  the 
tree  to  grow  faster.  There  is  no  scientific  basis  for  such 
a  practice,  and  while  there  is  usually  no  particular  harm 
done,  it  is  unlikely  that  any  real  advantage  results.  On 
the  other  hand,  trees  freshly  scored  in  this  way  are  very 
much  more  susceptible  to  injury  by  frost.  In  the  freeze 
of  January,  1913,  thousands  of  young  trees  were  lost  for 
no  other  reason  than  that  they  had  recently  been  scored 
on  the  southwest  side ;  and  as  a  result  of  the  cold  followed 


Fig.  63.  —  California  pruning  saw.     Used  throughout  the  Southwest. 

by  sunshine  the  entire  cylinder  of  bark  came  away  from 
the  trunk. 

From  the  time  the  young  trees  are  planted  in  orchard 
form  the  methods  of  pruning  oranges  and  lemons  diverge, 
and  it  is  best  to  discuss  them  separately. 

PRUNING    ORANGES 

It  has  long  been  the  custom  to  prune  orange  trees  very 
little  or  none  at  all  beyond  the  removing  of  water-sprouts 
and  dead  brush.  The  tree  resulting  from  this  system  is 
a  dense,  bushy  ball  of  foliage,  growling  close  down  to  the 


208  Citni.'i  Fruits 

ground,  with  the  fruit  distributed  over  the  surface  on  the 
ends  of  the  outer  limbs  and  twigs,  and  the  inside  an  imper- 
vious thicket  of  dead  brush  or  a  closely  shaded  open  space 
if  the  brush  has  been  removed.  While  such  trees  are  very 
beautiful  to  the  eye  and  produce  fairly  satisfactory  re- 
sults, they  fall  far  short  of  the  ideal  in  orange  pruning. 

Navel  oranges  of  true  standard  type  usually  need  little 
pruning  during  the  first  two  years  beyond  removing  water- 
sprouts.  If  the  Navels  are  from  poorly  selected  buds,  a 
good  many  will  throw  up  strong,  rude  branches  which  are 
often  more  or  less  thorny,  and  which  tend  to  monopolize 
the  tree  and  sap  the  strength  of  the  more  modest  growth. 
All  such  shoots  should  be  cut  off  early  in  their  career 
exactly  where  they  began.  The  best  branches  of  a  first- 
class  Navel  tree  naturally  become  more  or  less  pendant 
and  gradually  upon  such  horizontal  branches  upward  grow- 
ing shoots  arise.  These  shoots  are  dimorphic  in  character, 
and  every  pruner  should  learn  to  distinguish  between  them. 
One  form,  commonly  known  as  sucker  growth,  is  large  and 
rapid  growing,  reminding  one  of  a  young  shoot  of  aspara- 
gus. The  leaves  are  large  and  often  resemble  pomelo 
leaves.  Long  thorns  are  common,  although  a  sucker  may 
occasionally  lack  thorns  entirely.  Suckers  often  grow 
tW'O  or  three  feet  in  length  before  branching  or  making 
one  of  the  characteristic  nodes  which  mark  a  resting 
period. 

The  other  type  of  growth,  commonly  know^n  as  fruiting 
brush,  is  more  modest.  It  is  thick  set,  fine  stemmed,  and 
with  smaller  but  well  formed  dark  green  leaves.  This 
type  of  growth  will  branch  often  and  form  frequent  nodes 
and  manv  flower  buds.     The  character  of  a  shoot  is  not 


Pruning  and  Top-Working  209 

necessarily  determined  by  its  place  of  origin,  for  fruiting 
shoots  often  arise  from  the  trunk  or  main  branches  and 
have  access  to  large  food  supply  and  yet  do  not  develop 
into  suckers.  They  may  be  exceedingly  vigorous  and  erect 
with  very  large  leaves,  and  yet  terminate  at  six  inches 
in  a  flower  bud  and  mature  a  large,  more  or  less  coarse 
skinned  orange.  Suckers  usually  arise  from  branches  of 
some  size.  When  they  appear  low  down  on  the  trunk 
they  are  usually  called  water-sprouts,  although  there  is 
no  clear  distinction  between  the  two. 

A  sucker  left  alone  will,  after  a  few  years  of  riotous  living, 
quiet  down  and  produce  fine  brush  and  fruit.  The  first 
fruit  produced  will  be  more  or  less  coarse  and  inferior,  but 
the  quality  will  gradually  improve  from  year  to  year. 
INIany  experienced  growers  believe  that  suckers  will  never 
produce  fruit  fully  equal  in  quality  to  that  borne  by  other 
parts  of  the  tree.  Some  growers  also  claim  that  the  pres- 
ence of  a  large  sucker  in  a  Navel  tree  will  gradually  bring 
about  a  deterioration  in  the  quality  of  fruit  borne  on  older 
parts  of  the  tree  as  regards  shape,  color,  and  texture,  and  a 
diminution  of  the  quantity  as  well.  This  question  has 
been  a  common  bone  of  contention  at  Farmers'  Institutes 
and  Fruit  Growers'  meetings  in  California  for  years,  and 
there  is  as  yet  no  accurate  scientific  data  upon  which  to 
base  a  conclusion. 

Of  certain  things  we  are  sure,  however.  Suckers  do  pro- 
duce poor  fruit  for  several  years.  When  suckers  arise 
from  a  horizontal  limb,  they  are  apt  to  acquire  great 
leverage  when  in  fruit  and  often  twist  and  split  the  parent 
limb.  When  suckers  arise  from  u])right  branches  they 
are  usually  poorly  attached  and  are  apt  to  split  ofi'  with 


210 


Citrus  Fruits 


the  weight  of  fruit.  Suckers  destroy  the  symmetry  of  the 
tree  and  reflect  discredit  upon  the  orchardist.  When  a 
sucker  is  cut  back,  its  nature  will  not  be  changed  at  once, 
for  it  will  branch  and  give  rise  to  several  suckers  where 
one  was  before.  For  these  reasons  it  is  clear  that  as  far 
as  the  Navel  orange  is  concerned,  the  best  practice  is  to 
allow  the  tree  to  increase  in  size  slowly  and  develop  its 
top  out  of  the  fruiting  type  of  growth. 


Fig.  64.  —  A  good  type  of  pruning  saw  above.     Poor  type  below. 


The  two  types  of  wood  above  discussed  are  not  always 
clearly  differentiated,  and  intermediate  forms  are  often 
met  with.  Such  forms  are  often  puzzling  to  the  amateur 
pruner,  whose  best  policy  is  to  allow  them  to  remain  tem- 
porarily and  watch  future  tendencies.  In  every  case 
where  the  growth  is  clearly  a  sucker,  and  experienced 
pruners  find  little  difficulty  in  distinguishing  them,  they 
should  be  vigorously  suppressed. 

It  is  very  important  to  keep  a  careful  watch  for  bud- 


Pruning  and   Top-Working  211 

sports,  especially  in  old  Navel  trees  wliich  have  been 
propagated  from  carelessly  selected  buds.  The  same  sport 
will  sometimes  appear  many  times  on  different  trees  in  the 
same  orchard,  as  explained  in  Chapter  VII.  Some  growers 
confuse  sporting  branches  with  the  dimorphic  branches 
discussed  above,  while  in  reality  the  phenomena  are  quite 
distinct.  Sporting  involves  a  change  in  the  germ-plasm 
of  the  cells,  while  the  dimorphic  differences  mentioned 
do  not.     Sports  may  be  removed  while  the  branches  are 


Fig.  65.  —  One  of  the  best  types  of  pruning  shears. 


still  small  and  the  orchard  thus  kept  true  to  type  by  prun- 
ing. Occasionally  a  tree  may  be  encountered  which  ap- 
parently has  ever-sporting  tendencies.  This  is  due  to 
the  fact  that  the  mutation  occurred  in  the  trunk  early  in 
the  history  of  the  tree,  or  even  on  the  tree  from  which 
the  original  bud  was  taken,  and  the  mutative  cells  have 
multiplied  and  become  distributed  through  various  parts 
of  the  tree.  It  requires  very  drastic  pruning  to  cure  such 
a  tree  of  its  bad  habits,  and  it  is  often  advisable  to  pull  it 
out  and  plant  a  new  tree  in  its  place. 

It  is  well  for  the  pruner  to  bear  in  mind,  however,  that 


Citrus  Fruiti' 


wliilr  the  great  majority  of  sports  are  objectionable,  some 
of  our  improved  varieties  have  originated  as  sports,  and  it 
is  therefore  wise  to  critically  examine  the  fruit  of  every 
sport  discovered  before  destroying  it. 

Valencia  oranges  grow  in  quite  a  diiYerent  way.     They 

are  not  so  much 
given  to  erratic 
growth,  but  their 
fruiting  wood  is 
much  more  rapid 
growing  than  that 
of  the  Xavel,  and 
is  apt  the  second  or 
third  year  after 
planting  to  pro- 
duce a  number  of 
bare  canes  three 
or  four  feet  long 
which,  branching 
at  the  apex,  be- 
come overloaded 
w  i  t  h  fruit  a  n  d 
break  down.  It  is 
well  to  pinch  these 
shoots  and  force 
them  to  branch  be- 
fore they  groAv  too  long.  This  should  result  in  a  stronger 
framework  and  render  pro]:)ping  unnecessary-  in  future 
years. 

As  orange  trees  come  into  full  bearing,  the  weight  of 
fruit  bends  the  lower  branches  down  to  the  ground,  with 


Fig.  66.  —  Vigorous  fruiting  brush  growing  iu 
the  place  of  suckers. 


Pruning  and   Top-Worlcing  213 

the  result  that  uprights  loriii  upon  theui.  All  the  up- 
rights which  are  of  the  fruiting  type  of  growth  should  be 
allowed  to  remahi.  They  may  be  depended  upon  to  pro- 
duce a  large  proportion  of  the  crop.  Finally,  however,  the 
extremity  of  the  lower  mother  branch  becomes  weakened 
with  much  fruiting,  and,  bending  low  under  the  young 
growth,  becomes  smothered.  It  should  then  be  cut  back 
to  vigorous  growth  or  removed  altogether. 

In  order  that  the  short  fruiting  brush  along  the  larger 
limbs  shall  produce  a  greater  quantity  of  fancy  inside  fruit, 
it  must  have  light.  The  top  and  sides  of  the  tree  are  apt 
to  get  too  thick  and  keep  the  center  too  dark.  To  prevent 
this,  the  wall  of  foliage  should  be  opened  up  occasionally 
by  taking  out  bodily  a  few  small  branches  from  various 
places  in  the  walls  and  top.  These  holes  will  let  in  sun- 
light, which  shifts  as  the  sun  moves  across  the  sky.  This 
is  much  better  than  outraging  the  tree  by  cutting  out  the 
entire  top  at  one  time. 

It  is  necessary  to  go  over  all  bearing  trees  once  in  two 
years  to  remove  all  interfering  and  crossed  limbs,  as  well 
as  dead  brush,  and  to  thin  the  tops  somewhat.  The  trees 
should  also  be  examined  several  times  each  year,  and  any 
water-sprouts  appearing  on  the  trunk  or  main  branches 
removed. 

PRUKIXG    LEMONS 

Young  lemon  trees  should  be  cut  back  severely  from  the 
beginning.  They  should  be  curbed  in  their  riotous  growth 
and  forced  to  increase  in  size  slowly  and  by  the  addition 
of  the  more  or  less  crooked,  much  branched  fruiting  type 
of  wood.     The  tendency  of  the  lemon,  and  especially  the 


214 


Citrus  Fniiis 


Eureka  variety,  is  to  throw  out  long 
branches  which  fruit  at  the  ends.  These 
bend  ()\er  and  are  not  only  in  the  way  of 
cultivation  but  are  whipped  about  by  the 
winds  and  often  break  with  the  weight 
of  fruit.  The  main  object  should  be  to 
shorten  back  and  strengthen  the  scaffold 
or  main  limbs  in  order  that  they  may  carry 
their  load  nearer  the  center  of  the  tree  and 
be  stocky  and  stiff  enough  to  withstand 
strong  winds  without  swaying  and  thorn 
stabbing  the  fruit.  This  result  is  not 
always  easy  to  attain.  The  tendency  of 
lemon  trees  is  to  grow  rapidly  upward 
while  most  of  the  fruit  is  borne  on  more 
or  less  crooked  horizontal  branches.  Ac- 
cording to  the  Baronio  system,  which  is 
now  practically  abandoned,  the  trees  were 
absolutely  limited  to  horizontal  growth 
after  they  had  reached  a  height  of  about 
five  feet.  The  vital  trouble  with  this 
system  was  that  it  did  not  recognize  that 
on  deep,  rich  soil  a  lemon  tree  could  not 
produce  to  its  full  capacity  when  limited 
to  five  feet  in  height.  The  tendency  now 
is  toward  higher  trees.  With  lemons  at  a 
high  price  it  pays  to  climb  after  them, 
provided,  of  course,  that  the  number 
borne   near   the   ground   is   not  reduced 

Fig.    67.  —  This 

extra  vigorous  orange  shoot  terminated  at  six  inches  with  a  fruit,  show- 
ing that  excess  of  food  did  not  change  it  into  a  sucker. 


Pruning  and  Top-Working  215 

by  the  presence  of  the  high  tops.  It  is  the  writer's  behef 
that  in  deep,  rich  soil  the  economic  limit  of  bearing 
surface  of  the  lemon  tree  is  not  below  ten  feet. 

It  is  the  custom  of  some  growers  to  arbitrarily  decide 
upon  a  certain  height  and  then  shear  the  tops  to  this  line, 
making  the  trees  appear  from  above  as  flat  as  a  floor.  This 
shearing  process  results  in  the  brush  quickly  becoming  too 
thick.  It  is  much  better  to  select  those  branches  whicli 
reach  above  the  line  and  cut  them  off  at  their  junction 


Fig.  68.  —  A  sixty-acre  three-year-old  Valencia  orchard  top-worked  to 
lemons.     The  paper  bags  protect  the  buds  from  rose  beetles. 

with  the  mother  branch.  If  a  vigorous  upward  growing 
shoot  is  cut  back  for  a  part  of  its  length,  it  will  put  out 
several  shoots  which  continue  the  growth.  When  build- 
ing up  a  young  tree,  this  is  necessary,  in  order  to  make  the 
main  branches  more  stocky,  but  it  must  always  be  followed 
by  a  thinning  out  of  the  resulting  shoots. 

The  following  five  statements  are  in  the  nature  of 
maxims  and  should  form  the  basis  of  any  rational  system 
of  lemon  pruning.  They  are  accepted  by  the  majority  of 
lemon  growers : 

a.  Lemon  sap  flows  more  freely  in  vertical  branches, 


216 


Citrus  Fruits 


hence  vertical  branches  grow  at  the  expense  of  lateral 
ones. 

b.  A  lateral  crooked  branch  is  much  more  fruitful  than 
a  straight  upright  one. 

c.  Fruitfulness  and  high  quality  are  the  results  of  a  slow 
but  steady  circulation  of  the  sap. 

d.  The  finest  quality  fruit  is  borne  on  small  fruiting 
brush  on  the  interior  of  the  tree  and  the  sap  supply  of  such 
brush  should  be  protected  from  thieving  suckers. 

e.  The  wider  the  angle  the  stronger  the  limb.  Crotches 
with  acute  angles  often  split  down. 


Fifteen  months'  growth  on  stocks  shown  in  Fig.  68. 


Lemon  trees  may  be  pruned  at  any  time  of  the  year, 
but  it  is  customary  to  defer  removing  large  limbs  till  the 
time  when  there  is  the  least  amount  of  fruit  on  the  trees. 
This  usually  is  in  the  late  spring.  Some  of  the  larger 
ranchers  employ  pruners,  for  the  mature  trees,  who  work 
the  year  round.  They  confine  their  work  to  thinning  out 
the  fruiting  brush,  removing  interfering  and  broken 
branches  and  suckers  from  the  trunks.  In  addition  to 
this  a  special  group  of  pruners  go  over  the  trees  each 


Pruning  and   Top-Working  217 

spring  and  autumn  and  cut  out  the  superabundant  growth 
of  vegetative  shoots  in  the  tops. 

When  it  is  necessary  to  cut  oft'  large  hmbs  containing 
some  good  fruit,  it  is  wise  to  pick  this  fruit  from  the  Hmbs 
at  once.  If  this  is  not  done,  the  leaves  (being  separated 
from  the  roots)  will  draw  on  the  water  contained  in  the 
juice  of  the  lemons  and  dry  them  out  very  quickly, 

DISPOSITION    OF    PRUNINGS 

If  prunings  are  to  be  hauled  out  and  burned,  they 
should  be  removed  to  some  distance.  Citrus  trees  are 
extremely  susceptible  to  injury  from  the  heat  of  fires. 
However,  in  a  country  such  as  California  where  humus- 
forming  materials  are  scarce,  it  is  very  wasteful  to  burn 
prunings.  They  should  by  all  means  be  chopped  up  fine 
and  plowed  into  the  soil.  On  several  of  the  larger  ranches 
power  cutters  run  by  gasoline  engines  are  drawn  through 
the  orchards,  the  prunings  being  chopped  up  and  allowed 
to  lie  where  they  fall  till  succeeding  culti\ations  gradually 
work  them  into  the  soil.  On  other  ranches  the  prunings 
are  cut  up  with  hand  shears. 

PRUNING    FROSTED    TREES 

When  citrus  trees  are  injured  by  frost,  it  is  wise  to  defer 
pruning  several  weeks  or  until  it  is  perfectly  clear  just  how 
far  back  the  wood  has  been  killed.  After  the  line  of  de- 
marcation between  living  and  dead  wood  becomes  appar- 
ent, no  time  should  be  lost  in  taking  the  necessary  steps 
toward  reconstructing  the  top  in  the  best  way  with  the 
least  possible  loss  of  time. 


218  Citrus  Fruits 

The  problems  involved  in  mending  and  reforming  the 
tops  of  frosted  citrus  trees  fall  naturally  into  two  classes : 
those  having  to  do  with  very  young  trees  and  those  con- 
cerned with  large  mature  trees. 

Reheading  Young  Trees 

When  a  one-  or  two-year-old  tree  has  been  killed  to  a 
point  near  the  ground  it  should  first  be  determined  in  each 
individual  case  whether  the  dead  wood  extends  below  the 
bud  union.  If  there  remains  enough  live  wood  above  the 
union  to  grow  a  strong  shoot,  such  a  shoot  may  be  allowed 
to  grow  and  become  the  trunk  of  the  new  tree,  all  other 
shoots  being  suppressed.  If  on  the  other  hand  the  trunk 
is  killed  below  the  union,  it  will  be  necessary  to  set  a  new 
bud.  The  opportunity  is  thus  presented  of  reconsidering 
the  relative  profits  to  be  derived  from  oranges,  lemons,  or 
pomelos.  In  case  the  root  is  sweet  orange  the  bud  may  be 
set  immediately,  provided  there  is  sufficient  room  to  do  so 
without  excavating  the  soil,  for  in  no  case  should  a  bud  be 
set  below  the  soil.  In  case  the  trees  have  been  killed 
to  the  ground  it  is  well  to  select  the  most  vigorous  sprout 
and  bud  into  this  two  or  three  inches  above  the  ground. 
If  the  root  is  sour  orange  or  pomelo,  it  is  best  to  place  the 
bud  six  or  eight  inches  from  the  ground  on  a  strong  sprout. 
This  will  result  in  a  somewhat  hardier  tree  and  one  more 
resistant  to  gum-disease. 

In  all  cases  in  which  a  new  trunk  must  be  grown  on  trees 
already  planted  in  orchard  form,  it  is  necessary  of  course 
to  stake  the  trees  and  tie  them  every  few  inches,  taking 
care  to  disbud  often  and  remove  all  sprouts  from  the  root, 


Pruning  and  Top-Working  219 

eventually  heading  the  tree  at  the  desired  height.  A 
stake  larger  than  the  customary  building  lath  is  advisable 
in  order  to  pre\'ent  injury  bypassing  teams  and  tillage  tools. 

When  the  tops  of  young  trees  are  partly  frozen  it  will  be 
found,  especially  with  lemons,  that  the  more  rapid  grow- 
ing upright  shoots  have  been  killed,  while  the  fine  fruiting 
brush  has  been  spared.  Instead  of  cutting  back  all  these 
injured  shoots  in  proportion  to  the  injury,  it  is  much  better, 
especially  with  lemons,  to  take  out  most  of  the  very  strong 
upright  canes  entirely.  If  they  are  merely  cut  back  and 
allowed  to  remain,  each  one  will  throw  up  several  shoots, 
which  in  turn  must  be  cut  back,  the  final  result  being  a 
broom-like  growth  with  far  too  many  shoots.  The  proper 
pinching  and  thinning  of  such  a  multiplicity  of  shoots  will 
involve  much  more  labor  than  the  commercial  orchardist 
can  aflord.  It  is  better,  therefore,  to  remove  most  of  the 
upright  vegetative  shoots  entirely  and  rely  on  new  shoots 
from  the  horizontal  wood  to  enlarge  the  framework  of  the 
top.  All  water-sprouts  arising  from  the  trunk  and  around 
the  crotches  should  be  vigorously  suppressed.  It  is  a  good 
plan  to  whitewash  the  exposed  trunks  in  order  to  prevent 
sunburning  of  the  bark. 

It  often  happens  that  the  bark  of  the  trunks  of  young 
trees  will  be  split  by  the  frost  and  will  dry  out,  resulting  in  a 
strip  of  dead  bark  on  the  southwest  side.  This  condition 
is  not  necessarily  serious,  provided  there  remains  a  strip 
of  live  healthy  bark  of  sufficient  width  to  provide  a  flow  of 
sap  to  the  top.  The  living  l)ark  will  gradually  increase 
in  width  and  extend  over  the  dead  areas,  in  time  covering 
them  entirely.  In  order  to  prevent  the  entrance  of  wood- 
decaying  fungi  it  is  well  to  paint  the  dead  areas  with  white 


220  Citrus  Fruits 

lead,  asphiiltum  paint,  or  bordeaux  paste.  Bandaging  is 
often  resorted  to  in  order  to  prevent  the  injured  bark  from 
drying  away  from  the  wood.  Experience  has  shown  that 
this  is  of  httle  vahie  unless  it  is  done  immediately  or  within 
a  few  hours  after  the  injury.  On  a  large  acreage  it  is  im- 
practicable. 

Reheudiug  Mature  Trees 

Orange  trees  are  much  more  resistant  to  frost  than  lemon 
trees.  Over  c  ertain  large  areas  the  freeze  of  January,  191  ;^), 
ruined  the  fruit  and  completely  defoliated  the  trees  without 
killing  back  the  wood  to  an}'  appreciable  extent.  In 
such  a  case  the  trees  need  no  extra  pruning,  although 
while  the  leaves  are  absent  a  good  opportunity  presents 
itself  to  remove  conflicting  branches  and  thin  the  brush 
with  greater  ease  and  efficiency  than  is  possible  when  the 
trees  are  covered  with  leaves. 

Where  the  wood  is  killed  back  to  any  extent,  however, 
too  many  shoots  are  apt  to  start  from  the  live  wood  and 
many  suckers  appear  about  the  crotches.  Theoretically  the 
shoots  should  be  thinned  out,  leaving  only  what  is  needed. 
Those  left  will  be  stronger  and  bear  more  fruit  than  if  such 
a  large  number  were  allowed  to  struggle  for  life.  Practi- 
cally, however,  such  a  course  would  require  more  labor 
than  is  available  and  large  growers  will  have  to  adopt 
the  next  best  course,  namely,  that  of  cutting  out  all  the 
dead  wood  and  thinning  the  new  growth  by  taking  out 
bodily  a  certain  number  of  branches. 

Where  lemon  trees  have  been  killed  back  severely,  it 
is  best  to  withhold  or  decrease  the  fertilizer  during  the 
succeeding  year  in  order  that  a  more  moderate  growth 


Pruning  and   Top-Working 


221 


may  take  place.     Frozen  trees  have  been  thrown  out  of 
balance.     They  have  the  same  amount  of  root  as  before, 


Fig.  70.  —  Three-year-old  Navel  head  on  top-worked  sweet  seedling. 


which  is  now  pouring  sap  into  a  much  reduced  top.  The 
result  is  bound  to  be  a  tremendous  new  growth  breaking 
out  all  over  the  trunk  and  branches.     At  best  a  great  deal 


222 


Citrus  Fruits 


of  labor  will  be  required  to  properly  sucker  the  trees.  If 
additional  stimulation  is  brought  about  by  the  application 
of  quick-acting  fertilizers,  this  trouble  will  be  increased. 
Wise  lemon  growers  prefer  to  build  the  new  head  out  of 
the  more  moderate  growth  of  fruiting  wood  rather  than 
out  of  water-sprouts.  It  is  not  necessary  or  always  ad- 
visable to  root  prune  frosted  trees,  but  if  hardpan  or  plow- 
sole  exist,  it  may  be  broken  up  with  a  subsoil  plow  at  this 


time  with  less  injury  to  the  trees  from  cuttmg 
roots.  The  number  of  roots  which  may  be  cut  with 
impunity  will  of  course  depend  upon  the  amount  the  tops 
of  the  trees  have  been  killed  back. 

It  seems  reasonably  certain  that  no  injury  to  the  tree 
can  residt  from  any  of  the  materials  passing  from  the 
frozen  oranges  back  into  the  tree.  An  examination  of 
those  oranges  which  have  been  too  badly  frozen  to  be  fit 
for  shipment  shows  that  most  of  them  have  been  only 
partially  killed ;    consequently  they  are  presumably  re- 


Pruning  and  Top-Working  223 

spiring  carbon  dioxide.  This  loss  of  energy  would  be  saved 
if  the  oranges  were  removed  from  the  tree  rather  than  al- 
lowed to  hang  all  summer.  There  is  no  experimental 
evidence,  however,  to  show  whether  this  loss  is  sufficient 
to  warrant  the  cost  of  early  removal  by  hand.  In  case  the 
fruit  is  picked  off  the  trees  it  may  safely  be  plowed  under, 
thus  adding  humus  and  some  plant-food  to  the  soil. 
There  is  no  danger  of  the  soil  becoming  acid  as  a  result 
of  this  practice,  for  in  some  orchards  cull  lemons  and 
oranges  are  regularly  used  in  large  quantities  as  a  manure 
with  only  beneficial  results. 


TOP-WORKING    OLD    TREES 

It  often  becomes  desirable  to  change  an  orchard  from 
one  variety  to  another  by  top-working.  Any  variety 
of  citrus  tree  may  be  top-worked  to  any  other  variety, 
although  some  combinations  succeed  better  than  others. 
It  is  thought  that  Valencia  oranges  do  not  always  do  well 
when  worked  on  lemon.  Satsuma,  as  a  rule,  should  not 
be  worked  on  sour  orange. 

There  is  no  particular  difficulty  in  regard  to  this  process 
except  that  it  interferes  with  the  production  of  the  or- 
chard and  much  time  is  lost  during  the  transition  from  one 
variety  to  another. 

Top-working  may  be  accomplished  in  any  one  of  three 
ways : 

1.  By  cutting  off  the  entire  top  and  budding  directly 
into  the  trunk  or  large  limb  stubs. 

2.  By  cutting  the  top  back  to  large  stubs  and  allowing 
strong  shoots  to  grow,  and  later  budding  into  these  shoots. 


224  Citrus  Fruits 

3.  By  cutting  back  the  top  to  small  stubs  and  budding 
directly  into  these. 

This  last  method  entails  so  much  labor  and  trouble 
in  keeping  water-sprouts  down  that  it  is  little  used  except 
for  highly  prized  dooryard  trees. 

Some  growers  cut  the  entire  tops  off  as  soon  as  the  buds 
have  taken ;  others  leave  a  few  branches  to  draw  the  sap 
by  the  buds.  "  Safety  branches,"  as  they  are  called,  pre- 
vent the  buds  from  being  "  drowned  out  "  and  should 
be  left  when  top-working  is  done  in  late  spring  or  summer. 
Some  growers  cut  away  a  few  limbs  a  few  months  before 
budding  in  order  to  cause  the  old  bark  to  slip  better. 
The  thick  heavy  bark  of  old  limbs  or  trunks  should  be 
scraped  down  thin  immediately  surrounding  the  bud  at  the 
time  it  is  set.  Large  buds  should  be  used  and  in  many 
cases  they  take  better  if  the  bit  of  wood  which  is  severed 
with  the  bud  is  removed,  thus  bringing  together  larger 
areas  of  cambium. 

After  the  buds  have  begun  to  grow,  great  care  should 
be  taken  not  to  allow  any  sprouts  from  the  old  wood  to 
grow  up  and  crowd  them  out.  In  some  cases,  as  when 
lemon  is  worked  on  orange,  it  is  easy  to  tell  stock  from 
scion,  but  when  two  varieties  of  lemon  or  orange  are 
worked  together,  it  soon  becomes  very  difficult  to  tell 
which  is  stock  and  which  is  scion.  On  account  of  this 
difficulty,  and  for  other  reasons,  the  top-working  of  old 
orchards  is  practiced  to  a  much  smaller  extent  now  than 
formerly. 

When  an  old  orchard  is  top-worked,  the  trunks  should 
be  protected  by  whitewash  or  sacking,  for  sunburn  will 
be  almost  sure  to  result  from  the  exposure  of  the  bark. 


Pruning  and   Top-Working  225 


PRUNING    TOOLS 

The  operation  of  pruning  involves  the  making  of  wounds  ; 
and  since  these  wounds  heal  over  quickest  when  the  cut 
is  smooth  and  even,  it  foHows  that  any  tools  which  crush 
or  tear  the  bark  are  objectionable.  For  all  small  branches 
and  twigs,  a  strong  sharp  knife  is  ideal.  It  is  a  fact,  how- 
ever, that  for  economy's  sake,  some  form  of  hand  shears 
with  one  blade  and  a  guard  are  universally  used  in  com- 
mercial orchards.  For  larger  branches  the  two-handled 
lopping  shears  are  most  convenient.  For  removing  large 
limbs,  a  saw  is  necessary,  but  the  pruning  saw  with  teeth 
on  both  edges  should  be  avoided,  as  it  is  too  difficult  to  use 
without  damaging  the  tree.  By  far  the  best  saw  for  use 
in  a  citrus  orchard  is  that  known  as  the  "California" 
pruning  saw  (Fig.  03)  with  reversible  and  detachable 
blade.  The  blade  of  this  saw  may  be  turned  in  any  direc- 
tion, and  it  is  especially  convenient  for  work  in  close 
places.  It  is  very  important  to  keep  all  pruning  tools 
sharp.  A  half  dozen  extra  saw  blades  should  enable  the 
pruner  to  keep  a  sharp,  well-set  saw  in  hand  at  all  times. 

A  satisfactory  outfit  for  the  citrus  tree  pruner  may  be 
enumerated  as  follows : 

1.  A  short,  light  stepladder. 

2.  One  pair  strong  leather  gloves. 

3.  One  pair  hand  shears  (Henckel's  special  No.  9  pre- 
ferred) . 

4.  One  California  pruning  saw  (six  extra  blades). 

5.  One  B.  &  H.  special  pruning  saw. 

6.  One  pair  lopping  shears  with  riveted  wooden  handles. 

7.  Bucket  of  paint  with  brush  for  dressing  large  wounds. 

Q 


226  Citni^^  Fruits 


WOUNDS    AND    DRESSINGS 

All  large  limbs  should  be  sawed  off  close  to  the  trunk 
or  mother  limb  in  such  a  way  that  new  bark  will  grow  over 
the  cut  surface  from  all  directions.  This  takes  place  most 
readily  when  the  cut  surface  is  parallel  to  the  mother  limb. 
Stubs  are  a  source  of  danger  to  the  tree  and  reflect  dis- 
credit upon  the  orchardist.  When  a  sucker  is  cut  off  and 
even  a  very  short  stub  left,  other  suckers  will  put  out  from 
the  same  point  until  there  is  formed  what  is  known  as  a 
"  sucker-nest."  This  is  very  objectionable,  and  when  such 
"  sucker-nests  "  are  found  in  old  trees  they  should  be  re- 
moved cleanly  with  one  cut  of  the  saw,  going  well  into  the 
wood  in  order  to  stop  any  further  growth  of  suckers  from 
that  point. 

It  requires  several  years  for  a  large  wound  to  heal  over 
entirely,  and  during  this  time  it  is  susceptible  to  infection 
by  various  fungi  which  cause  the  wood  to  decay.  The  fine 
checks  in  the  wood  which  form  as  the  wound  dries,  are 
ideal  lodging  places  for  the  spores  of  decay-producing  or- 
ganisms. Decay  often  slowly  works  its  way  back  into  the 
trunk  and  causes  hollow  center.  Decayed  wood  in  the 
heart  of  a  tree  weakens  it  and  brings  on  a  diseased  condi- 
tion. Fortunately  it  is  a  simple  matter  to  prevent  this  by 
disinfecting  the  wounds  and  applying  some  dressing  which 
will  protect  the  exposed  wood  while  it  is  healing  over. 

In  the  case  of  pruning-wounds  where  small  limits  are  re- 
moved it  hardly  pays  to  go  to  the  expense  of  disinfecting 
the  wounds  before  the  dressing  is  applied.  In  tree  surgery, 
however,  where  large  cavities  are  chiseled  out  and  where 
large  limbs  are  removed,  it  is  well  to  apply  a  coat  of  liquid 


Pruning  and  Top-Working  227 

creosote  to  sterilize  the  wound  and  after  this  has  dried 
the  waterproof  dressing  may  be  used. 

The  matter  of  complete  covering  is  of  the  utmost 
importance.  Wound  dressings  should  exclude  the  air  and 
render  the  cut  surface  impervious  to  water.  As  infection 
may  take  place  through  a  very  small  opening,  time  and 
labor  are  entirely  wasted  unless  the  wounds  are  com- 
pletely covered. 

A  large  number  of  substances  which  vary  widely  as  to 
cost  and  convenience  of  application  are  used  for  dress- 
ing wounds.  As  a  rule  those  which  require  heating  be- 
fore application  are  not  to  be  recommended,  because  it  is 
too  much  trouble  to  carry  a  portable  fire  in  the  orchard, 
and  the  hot  sun  in  summer  is  apt  to  cause  them  to  melt 
and  leave  the  wound.  Out  of  a  large  number  of  formulse 
three  have  been  selected  for  mention  here.  No.  1  is  satis- 
factory for  small  jobs  in  yards  and  gardens,  but  is  much 
more  expensive  than  No.  2,  which  should  be  used  in  all 
large  orchards : 

No.  1. 


Alcohol 

6oz. 

Turpentine 

1  oz. 

Tallow 

2oz. 

Rosin 

lib. 

Heat  the  tallow  and  rosin  together,  cool  slightly,  and  add 
alcohol.  Then  stir  in  the  turi)entine.  This  may  be  used 
cold. 

No.  2.  Asphaltum  paint.  Heat  the  asphaltum  till 
thoroughly  melted  and,  after  removing  to  a  safe  distance 
from  fire,  dilute  with  benzine  to  make  a  mixture  which 


228  Citrus  FndU 

when  cokl  is  of  the  consistency  of  thick  paint.  As  the 
asphaltum  varies  greatly  in  density,  no  definite  proportion 
of  benzine  to  asphaltum  can  be  stated.  Asphaltum  tree 
paint  may  be  bought  in  cans  already  mixed,  but  is  much 
more  expensive  in  this  form. 

When  on  account  of  gum-disease,  wind  breakage,  top- 
working,  or  other  reasons  the  trunks  of  old  trees  are  exposed 
to  the  sun,  they  should  be  protected  with  a  coat  of  tree 
whitewash  or  bordeaux  paste  or  No.  3. 

No.  3.  I  1  lb.  copper  sulfate  or  bluestone 

I  3  qt.  water 
,      I  2  lb.  quick  lime 
I,  3  qt.  water 

Solutions  a  and  h  should  be  prepared  separately  before 
being  mixed  together. 

Tar  is  often  recommended  as  a  wound  dressing,  but  coal 
or  gas  tar  should  be  avoided,  as  it  usually  contains  com- 
pounds which  are  injurious  to  the  bark  of  citrus  trees. 
Most  of  these  injurious  compounds  are  volatile  and  may 
be  driven  off  by  boiling  the  tar,  but  even  the  boiled  tar 
has  no  advantage  over  the  asphaltum  paint. 

Small  cuts  heal  over  quickly  and  are  usually  so  numer- 
ous that  it  would  hardly  pay  to  apply  the  dressing.  Ordi- 
narily cuts  less  than  one  inch  in  diameter  are  not  dressed 
unless  they  are  conveniently  situated. 

Often  in  old  neglected  orchards  trees  will  be  found  in 
which  decay  has  worked  its  way  back  into  the  wood  of  the 
trunks.  The  proper  treatment  of  such  cases  involves 
tree  surgery,  the  methods  of  which  have  been  well  de- 
scribed and  illustrated  by  J.  F.  Collins  in  the  United  States 


Pruning  and  Top-Working  229 

Department  of  Agriculture  Yearbook  for  1913,  pages  163 
to  190.  It  is  necessary  of  course  to  remove  all  of  the  de- 
cayed and  discolored  wood  by  means  of  suitable  tools 
such  as  chisels  and  scrapers.  After  the  cavity  has  been 
carefully  cleaned  out  it  should  be  sterilized  with  creosote 
and  then  given  a  coat  of  asphaltum  paint.  The  cavity 
may  then  be  filled  with  cement  (1  part  of  cement  to  3  of 
sand).  It  is  necessary  to  undercut  the  cavity  somewhat 
after  the  fashion  of  a  dentist  preparing  a  cavity  in  a  tooth, 
in  order  that  the  block  of  cement  may  be  held  in  place. 
Sometimes  nails  are  driven  in  large  cavities  for  the  same 
purpose.  After  the  cement  has  hardened  the  whole 
job  should  be  painted  over  and  thoroughly  waterproofed. 
It  is  wise  to  inspect  such  work  at  least  once  a  year  and  re- 
paint if  not  entirely  waterproof. 

If  properly  treated,  such  cavities  will  heal  over  in  a  few 
years  and  the  tree  will  be  saved  and  greatly  strengthened. 

It  is  a  common  thing  for  the  main  branches  of  old  lemon 
trees  which  have  been  improperly  headed  to  split  down 
under  the  load  of  fruit.  Such  branches  may  be  saved  for 
many  years  of  usefulness  by  bolting.  Auger  holes  should 
be  bored  directly  through  the  trunk  and  large  iron  bolts 
with  washers  used.  It  is  important  in  such  cases  also  to 
carefully  disinfect  the  wounds  made,  and  dip  the  bolts 
and  washers  in  bordeaux  paste  before  inserting.  On  ac- 
count of  prevalence  of  the  gum-disease  organisms  and  the 
ease  of  inoculation  disinfection  is  especially  important. 
The  cracks  in  the  trunk  should  be  filled  with  bordeaux 
paste  before  they  are  drawn  together.  The  bolt  heads 
and  the  exterior  of  the  cracks  should  be  given  a  coat  of 
asphaltum  when  the  work  is  complete. 


CHAPTER   XIV 

FROST   AND   ORCHARD   HEATING 

Perhaps  no  phase  of  citriculture  has  advanced  with 
more  rapid  strides  during  the  last  few  years  than  orchard 
heating.  For  hundreds  of  years  in  certain  parts  of  pAirope 
some  protection  to  vineyards  and  gardens  has  been  se- 
cured in  a  crude  way  by  smudging.  The  modern  science 
of  orchard  heating  as  practiced  to-day,  however,  has  been 
developed  within  the  past  fifteen  or  twenty  years.  More- 
over this  subject  is  of  such  vital  interest  to  every  citrus 
growler  that  it  is  considered  well  worth  while  to  discuss  the 
matter  more  or  less  in  detail. 

HISTORICAL    COLD    PERIODS 

In  Blodget's  "  Climatology,"  published  in  1857,  we  find 
mention  of  a  cold  period  as  early  as  1748  which  caused  con- 
siderable damage  to  the  tropical  fruits  of  the  South. 
Other  cold  periods  occured  in  Plorida  in  176G,  1780,  1800, 
1835,  1852,  1876,  1886 ;  and  in  1894-95,  the  memorable 
double  freeze  occurred  which  almost  wiped  out  the  citrus 
orchards  of  Florida  and  changed  the  geography  of  the 
citrus  industry  there.  Cold  periods  may  therefore  be  ex- 
pected to  recur  at  intervals  of  about  twenty  years. 
230 


Frost  and  Orchard  Heating  231 

In  California  the  available  records  do  not  extend  so  far 
back.  In  1882  a  severe  freeze  was  experienced,  a  mini- 
mum of  21°  F.  being  registered  at  Fresno.  Ice  was 
formed  in  Los  Angeles,  and  the  surrounding  hills  were 
covered  with  snow.  Other  cold  periods  occurred  in  1888, 
1891,  1895,  1899,  1911,  and  1913.  Frosts  occur  in  Cali- 
fornia at  average  intervals  of  five  or  six  years.  Fortu- 
nately California  has  not  so  far  experienced  a  frost  ap- 
proaching in  severity  the  one  which  visited  northern 
Florida  in  1894-95.  It  should  be  pointed  out,  however, 
that  the  great  damage  in  Florida  was  not  due  so  much  to 
the  severity  of  the  frost  as  it  was  to  the  peculiar  relations 
of  the  two  cold  periods.  The  first  denuded  the  trees  of 
foliage  and  fruit  and  was  followed  by  a  period  of  warm 
weather.  When  the  new  growth  was  pushing  vigorously 
and  the  tender  shoots  were  about  four  inches  long,  the 
second  freeze  came  and  killed  the  trees  to  the  ground. 

The  freeze  of  January,  1913,  was  the  most  damaging  in 
the  history  of  California,  and  in  the  southern  part  of  the 
state  the  temperature  was  lower  than  had  been  known  for 
a  period  of  sixty  years.  Heavy  frosts  occurred  on  Janu- 
ary 4,  5,  6,  7,  and  8.  Strong  wdnds  preceding  the  frosts 
came  from  the  north  and  northwest  rather  than,  as  usu- 
ally happens,  from  the  northeast.  The  wind  began  to 
blow  shortly  after  noon  on  January  4,  and  continued  until 
3  A.M.  on  January  6.  Instead  of  the  usual  draught  through 
Cajon  Pass  at  an  elevation  of  3823  feet,  the  winds  came 
directly  over  the  Sierra  Madre  Range,  whose  elevations 
exceed  (iOOO  feet.  During  the  midday  hours  on  the  4th, 
5th,  andOth,  the  temperature  did  not  rise  much  above  50°  F. 
and  in  some  places  did  not  reach  50°  F.     Apparently  the 


232  Citrus  Fruits 

whole  mass  of  air,  to  an  elevation  of  several  thousand  feet, 
was  at  a  low  temi)eratiire.     The  wind  was  extremely  dry. 

During  this  freeze  the  fruit  was  subjected  to  tempera- 
tures below  freezing  for  four  successive  periods,  averaging 
four  hours  for  the  first,  thirteen  hours  for  the  second, 
thirteen  hours  for  the  third,  and  nine  hours  for  the  fourth. 
In  all,  during  a  total  period  of  72  hours,  during  which, 
under  normal  conditions,  the  trees  would  have  received  a 
supply  of  heat  approximately  represented  by  1500  hour- 
degrees,  starting  from  a  temperature  of  40°  F.,  they  only 
received  220  hour-degrees.  There  w'ere  170  hour-degrees 
below  freezing,  and  of  these  50  were  below  25°  F. 

Minimum  temperatures  of  13°  were  recorded  at  Escon- 
dido ;  16°atChino;  17°  at  Pomona;  18°  at  Redlands ; 
21°  at  Riverside  and  Pasadena;   and  25°  at  San  Diego. 

This  cold  period  destroyed  at  least  ten  million  dollars' 
worth  of  fruit,  to  say  nothing  of  the  damage  to  the  trees. 
Yet  the  industry  recovered  very  quickly,  and  in  1913-14 
the  normal  amount  of  fruit  was  marketed.  During  this 
trying  period  the  practical  value  of  orchard  heating  was 
clearly  demonstrated.  Orange  growers  who  were  properly 
equipped  saved  their  crops,  and  lemon  growlers  also  saved 
their  crops  and  trees  and  in  some  cases  marketed  sufficient 
fruit  the  following  summer  at  very  high  prices  to  pay  the 
entire  cost  of  their  heating  equipment  several  times  over. 

With  deciduous  fruits,  the  damage  is  done  by  late  spring 
frosts  which  occur  after  the  trees  have  blossomed.  It  is 
only  necessary  therefore  to  be  prepared  for  orchard  heating 
during  afew^  wrecks  in  March  and  April.  With  citrus  fruits, 
however,  it  is  very  different.  The  fruit  hangs  on  the  trees 
all  winter,  and  it  is  necessary  to  be  prepared  to  heat  the 


Frost  and  Orchard  Heating  233 

orchards  at  any  time  between  November  15  and  ^larch  15 
or  for  a  period  of  four  months. 

FORECASTING    FROSTS 

There  are  several  ways  by  which  plants  lose  their  heat. 
When  two  bodies  at  different  temperatures  are  in  contact, 
they  tend  to  become  alike  in  temperature  by  the  direct 
conduction  of  heat  from  the  particles  of  the  warmer  body 
to  those  of  the  cooler.  Thus  it  is  that  the  earth  and  living 
plants  upon  it,  having  become  warmed  by  the  sun,  lose  part 
of  their  heat  to  the  atmosphere  lying  directly  above  them, 
tiirough  this  process  of  conduction.  This  heat  is  con- 
ducted slowly  upwards  in  the  air.  Air,  however,  is  a  poor 
absorber  and  conductor  and  would  become  warmed  only 
very  slowly  were  it  not  for  another  process  of  greater  im- 
portance which  soon  begins  to  act. 

Air,  like  all  other  gases,  expands  and  becomes  lighter 
upon  heating.  Therefore,  the  air  at  the  surface  of  the 
earth  which  has  become  heated  by  conduction,  rises,  and 
its  place  is  taken  by  the  colder  air  from  above.  A  kind 
of  circulation  is  thus  set  up,  somewhat  resembling  that  in 
a  vessel  of  water  which  is  being  heated. 

In  the  horizontal  movements  of  the  air,  which  we  call 
winds,  the  process  of  convection  also  comes  into  play. 
When  a  cold  wind  is  blowing,  as  every  one  knows,  the 
heat  of  exposed  bodies  will  be  rapidly  carried  away. 

By  still  another  means  is  the  heat  of  the  earth  and  trees 
lost  to  the  air  above.  It  is  expended  in  the  process  of 
evaporating  moisture  from  their  surfaces.  The  heat 
thus  lost  is  commonly  said  to  have  been  changed   into 


234  Citrus  Fruits 

latent  heat ;  it  is  really  not  heat  at  all  in  this  latent  con- 
dition, but  is  simply  the  enerj^y  needed  to  overcome  the 
intermolecular  attractions  of  the  evaporating  substance. 
Evaporation  may  be  of  considerable  importance  in  lowering 
the  temperature  of  vegetation,  especially  when  the  air  is  dry. 
But  the  three  processes  just  mentioned  are  by  no  means 
sufficient  to  account  for  the  tremendous  loss  of  heat  which 
occurs  on  a  quiet,  clear  night  when  freezing  temperatures 
are  most  likely  to  occur.  The  fourth  and  much  more 
important  way  by  which  heat  is  lost  is  by  that  peculiar 
process  known  as  radiation.  By  this  process  the  vibratory 
heat  motion  of  a  body  is  transferred  in  part  to  the  ether, 
setting  up  in  it  waves  which  proceed  outward  along  straight 
lines  and  in  all  directions,  in  the  same  manner  that  sound 
waves  emitted  by  a  vibratory  tuning-fork  proceed  out- 
ward in  all  directions  through  the  air.  The  surface  of  the 
earth  is  continually  losing  heat  by  radiation  into  space; 
but  during  the  day  it  usually  receives  heat  more  rapidly 
from  the  sun  than  it  loses  it  by  radiation,  and  therefore 
it  grows  warmer.  At  night,  however,  when  the  sun's 
heat  is  cut  off,  the  effect  of  loss  of  heat  by  radiation  is  not 
counterbalanced  and  the  earth's  temperature  conse- 
quently falls.  Radiation  takes  place  more  rapidly  from 
the  surface  of  plants  than  it  does  from  the  air  about  them, 
so  that,  on  still  nights,  these  surfaces  are  frequently  cooled 
several  degrees  below  the  temperature  of  the  surrounding 
air. 

Factors  influencing  the  Occurrence  of  Frost 

Wind,  relative  humidity,  and  absence  of  clouds  and  dust, 
all  influence  the  occurrence  of  frost.     On  still  nights  the 


Frust  and  Orchard  Heating  235 

air  as  it  cools  arranges  itself  in  strata,  the  coldest  and 
heaviest  next  the  ground.  Wind  tends  to  mix  the  air  and 
bring  it  all  to  the  same  temperature,  which  of  course 
would  mean  an  increase  in  the  temperature  of  that  next 
the  ground  which  is  in  contact  with  the  plants. 

Atmospheric  moisture  lessens  cold  in  two  ways :  first, 
it  retards  the  escape  of  the  day's  heat  by  radiation  at 
night ;  second,  the  latent  heat  of  the  vapor  becomes 
sensible  heat  when  the  condensation  of  the  vapor  takes 
place.  The  indirect  influence  of  the  water  vapor  in  the 
air,  in  checking  radiation  from  the  earth,  is  a  powerful 
conservator  of  heat. 

When  moist  air  is  cooled,  it  will  finally  reach  a 
temperature  of  saturation  which  is  known  as  the  "  dew 
point,"  when  no  more  water  vapor  can  be  held  at  that 
temperature.  When  cooled  further,  water  will  be  de- 
posited as  liquid  drops  (dew)  if  the  temperature  is  above 
freezing  point,  or  as  ice  crystals  (frost)  if  below  the  freez- 
ing point.  Now,  when  water  vapor  is  changed  into 
liquid  form,  a  large  amount  of  heat  is  liberated  —  the 
same  amount  which  is  required  to  change  the  same 
quantity  of  w^ater  into  vapor.  This  liberated  heat  be- 
comes available  to  warm  the  air.  It  is  said  that  the 
precipitation  of  one  quart  of  dew  will  liberate  enough 
heat  to  raise  the  temperature  of  1000  cubic  feet  of  air 
25°  F.' 

Clouds  also  have  a  marked  influence  in  preventing  the 
escape  of  heat  from  the  earth;  they  reflect  or  radiate 
back  to  the  earth  the  heat  which  escapes  from  it.    There- 

'  W.  H.  Hammon,  "Protecting  Orchards  Against  Frost," 
Bui.  No.  70,  California  State  Board  of  Horticulture,  1895. 


236  Citru.<i  Fruits 

fore,  frosts,  as  a  rule,  do  not  occur  on  cloudy  niijhts,  and 
tlie  clouding  up  of  the  sky  during  the  evening  may  often 
prevent  expected  frost.  Dust  and  smoke  suspended  in 
the  air  act  in  much  the  same  way  as  clouds. 

The  conditions  favorable  for  a  freeze  may  then  be 
summarized  as  follows : 

1.  A  clear  sky;  thus  furnishing  no  check  to  loss  of 
heat  from  the  earth  and  trees  by  radiation. 

2.  Dry  air;  because  cooling  by  radiation  will  then 
continue  to  a  much  lower  temperature  before  being 
checked  by  the  heat  liberated  in  condensation. 

3.  Still  nights;  because  the  air,  not  being  mixed  by 
the  wind,  arranges  itself  in  layers  according  to  its  density, 
with  the  colder,  heavier  air  beneath  in  contact  with 
vegetation. 

4.  Very  cold  dry  north  winds  which  abate  before  dawn. 

5.  A  comparatively  smoke  and  dust  free  atmosphere. 

Local  Conditions  affecting  Frost 

Practically  every  citrus  district  in  California  has  its 
frosty  and  its  frostless  spots.  Even  on  the  same  ranch 
the  line  is  often  clearly  drawn  between  safe  and  dangerous 
ground.  There  are  several  reasons  for  this.  In  the  first 
place  it  is  well  known  that  frost  is  less  likely  to  occur  at 
moderate  elevations,  or  on  low  hillsides,  than  in  low-lying 
valleys  and  depressions.  This  is  caused  by  what  is 
known  as  "  inversion  of  temperatures."  On  a  hillside  or 
bench  land  with  good  slope,  the  air,  as  it  cools  and  grows 
heavier,  will  flow  ciuietly  downward  and  collect  in  the  low- 
lands, thus  crowding  the  warmer  air  upward.     This  warm 


Fro.s-t  and  Orchard  Ilcat'uuj  2'.M 

air  floating  on  top  spreads  out  to  the  hillside,  to  which 
it  imparts  a  portion  of  its  heat.  And  so  a  gentle  but 
complex  circulation  is  kept  up  which  accounts  for  the 
warming  of  one  spot  or  belt  and  the  cooling  of  another. 
Often  there  are  unknown  local  factors  influencing  this 
circulation  which  makes  it  very  difficult  to  foretell  on 
any  giyen  hillside  just  where  the  thermal  belt  will  be. 
This  is  due  no  doubt  to  various  unseen  cross-currents 
caused  by  the  irregularities  of  the  mountains.  Again,  a 
valley  is  usually  shaded  for  a  longer  period,  both  in  the 
morning  and  afternoon,  than  all  the  uplands ;  therefore 
it  goes  into  the  night  with  a  less  store  of  heat  with  which 
to  counteract  freezing  temperatures. 

The  type  of  frost  just  described  is  the  normal  kind 
experienced  in  California  and  is  known  locally  as  a  "  gravity 
frost."  This  type  of  cold  weather  is  comparatively  easy 
to  combat  with  orchard  heaters.  Occasionally,  however, 
the  conditions  are  reversed,  as  was  so  well  exemplified  in 
the  "  blizzard  "  of  January,  1913.  During  this  period 
the  cold  north  wind  sweeping  directly  down  from  over 
the  mountain  tops,  6000  feet  in  height,  caused  the  trees 
on  the  uplands  or  thermal  belts  to  suffer  more  severely 
than  those  planted  on  lower  land,  as  were  the  orchards  of 
Orange  County. 

Conditions  indicating  Frost  in  California^ 

The  condition  preceding  frost  in  California  is  indicated 
by  the  passage  of  a  low  barometer  area  from  Idaho  south- 

'  Adapted  from  A.  G.  MeAdie's  "Frost  Fighting,"  U.  S. 
Weather  Bureau,  Nos.  29  and  219. 


238  Citrus  Fruits 

ward  across  Utah,  thence  westward  into  southern  Nevada, 
and  finally  southward  into  southern  California.  For  the 
most  part,  frosts  are  due  to  the  movement  of  cold  air 
from  the  northeast.  Frosts  also  occur  when  a  low 
area  over  southern  California  moves  rapidly  southeast 
and  is  followed  by  a  high  wind  from  northern  California. 
Conversely,  when  the  air  moves  from  the  sea  inland,  there 
is  little  danger  from  frost. 

The  topography  of  southern  California  favors  drainage 
of  the  air  from  the  mountains  seaward  at  certain  hours, 
and  a  return  movement  of  the  surface  air  inland  at  cer- 
tain hours.  Thus  conditions  are  highly  favorable  for  the 
formation  of  air  streams,  which  reverse  their  direction  at 
least  twice  in  each  24-hour  period. 

In  general,  the  lower  air  flows  to  the  southwest  during 
the  night  and  early  morning,  and  to  the  northeast  during 
the  afternoon.  During  the  winter  months,  when  areas 
of  high  pressure  pass  over  the  Great  Basin,  the  surface 
air  apparently  moves  south,  crossing  the  northern  flank 
of  the  Sierra  Madre  and  descending  with  some  momentum 
into  the  Great  Valley.  The  wind  movement  is  particu- 
larly marked  in  the  vicinity  of  mountain  passes. 

During  these  so-called  "  northers,"  the  temperature 
rises  and  the  humidity  falls.  The  existence  of  a  low 
pressure  area  south  of  the  Colorado  seems  to  intensify 
this  condition.  Heavy  frosts  occur,  as  a  rule,  after  a 
period  of  high  north  winds,  and  are  traceable  to  the  dis- 
placement of  the  warm  air  in  the  valley  by  cooler,  very 
dry  air.  This  dry  air  permits  very  rapid  radiation,  and 
when  the  svind  lulls,  which  is  apt  to  occur  after  sunset, 
the  drop  in  temperature  is  very  rapitl. 


Frost  and  Orchard  Heating 


239 


HOW    PLANTS   ARE    INJURED    BY    COLD 

In  the  U.  S.  Department  of  Agriculture  Yearbook  for 
1895,  B.  T.  Galloway  describes  what  takes  place  when 
plant  tissues  freeze,  very  concisely  as  follows : 

"  All  the  phenomena  involved  in  the  freezing  of  succu- 
lent and  other  plants  depends  on  the  condition  of  the 
protoplasm  or  living  matter  in  the  plant  cell.  If  the 
temperature  is  suffi- 
ciently low  to  cause 
a  chemical  disorgan- 
ization of  the  living 
substance,  the  part 
of  the  plant  where  this 
takes  place  dies.  If, 
on  the  other  hand,  no 
actual  disorganiza- 
tion of  the  cell  con- 
tents occurs,  the  af- 
fected parts  may 
recover.  It  is  hardly 
necessary  here  to  en- 
ter upon  a  discussion 

of  the  various  phenomena.  Suffice  it  to  say  that 
under  the  influence  of  cold  the  water  in  the  cells 
escapes,  and  may  be  frozen  either  in  the  spaces 
between  the  cells  or  on  the  surface  of  the  leaf,  stem, 
or  whatever  the  part  may  be.  As  the  temperature 
rises  this  frozen  water  may  again  be  taken  up  by  the 
cells,  and  in  such  cases  little  or  no  injury  results.  If  for 
any  reason,  however,  the  cells  are  not  able  to  regain  the 


\ 


-^=^ 


Fig.  72.  —  A,  normal  vesicles  of  lemon; 
B,  enlarged  vesicles  from  frosted  fruit, 
six  months  after  injury.      (Nat.  size.) 


240  Citrws'  Fruits 

water  Avithdrawn  by  the  cold,  injury  or  even  death  may 
result.  In  many  cases  the  rai)idity  with  which  the  ice  is 
thawed  has  a  marked  effect  on  the  abihty  of  the  cells  to 
regain  their  normal  condition.  If  the  thaw  is  gradual, 
the  water  is  furnished  no  faster  than  the  cells  can  absorb 
it,  and  equilibrium  is  therefore  soon  restored,  the  chemical 
processes  which  were  checked  during  the  freeze  are  re- 
sumed, and  the  plant  soon  regains  its  normal  condition. 
With  a  rapid  thaw,  however,  the  cells  are  not  able  to  take 
up  the  water  as  fast  as  it  is  furnished,  and  as  a  result 
chemical  decomposition  sets  in  and  death  follows.  Death 
in  this  case  is  essentially  the  same  as  that  which  results 
from  drought.  The  cell  loses  water  to  such  an  extent 
that  it  is  not  again  able  to  become  turgid,  and  as  a  result 
it  finally  withers  and  dies." 

That  the  above  is  equally  true  in  the  case  of  citrus 
fruits  has  been  shown  by  Bioletti.^  "  Frozen  and  un- 
frozen oranges  from  the  same  tree  were  received  —  with 
the  request  to  deteniiine  whether  the  cells  of  the  frozen 
oranges  had  burst  and  whether  this  was  the  cause  of  the 
rapid  drying  up  of  the  frozen  fruit.  INIicroscopic  exami- 
nation showed  no  difference  in  the  cells  of  the  two  kinds. 
Pieces  of  the  flesh  of  both  kinds  were  placed  in  a  water 
solution  containing  33  per  cent  of  cane  sugar,  and  other 
pieces  in  distilled  water.  The  next  day  the  cells  of  both 
kinds  in  the  sugar  solution  had  shrunk  equally,  while 
the  cells  of  those  in  distilled  water  had  swollen  equally ; 
indicating  that  there  were  no  breaks  in  the  cell  walls  of 
the  frozen  oranges." 

The  condition  of  the  plant,  whether  in   a  period  of 

1  California  Agr.  Exp.  Sta.  Rpt.,  1897-98,  p.  184. 


Frost  and  Orchard  Ilrafiiif/ 


241 


succulent  growth  or  in  u 
dormant  state  at  the  thiie 
of  low  temperature,  has  an 
important  bearing  upon 
the  limit  of  desiccation  of 
the  individual  cell,  dormant 
plants  being  able  to  with- 
stand lower  temperatures 
than  those  growing  rapidly. 

The  moisture  from  the 
cells  of  frozen  oranges  either 
evaporates  through  the 
rind  or  passes  out  through 
the  stem  and  is  transpired 
by  the  leaves.  The  tissues 
of  frosted  fruit  usually  bear 
small  white  specks  of  hes- 
peridin,  evidently  fonned 
by  chemical  changes.  The 
surface  ordinarily  shows 
very  little  indication  of 
injury,  although  the  inside 
tissues  may  be  dry  and 
shrunken.  While  frozen 
citrus  fruits  may  occasion- 
ally be  bitter  in  taste,  no 
injury  has  ever  been  known 
to  follow  their  use  even 
when  eaten  in  large  quantities. 

Leaves  of  citrus  trees  which  have  been  frosted  at  first 
curl  up ;   they  may  remain  upon  the  tree  and  recover  to 


Fit;.  73.  —  Bark   on   fruitinR   brush 
of  lemon  split  by  frost. 


242  Citrus  Fruits 

a  certain  extent,  or  fall  off  after  a  few  days.  Defoliation 
may  occur  without  serious  injury  to  the  smaller  branches. 
The  injury  to  branches  naturally  depends  upon  the  degree 
of  dormancy  and  the  diameter  of  the  branch ;  the  twigs 
and  smaller  branches  may  be  cut  back  seriously  by  frost 
without  any  appreciable  injury  to  the  larger  parts.  A 
very  common  form  of  frost  injury  to  young  trees  is  the 
splitting  of  the  bark  along  the  trunk  and  lower  branches ; 
the  cracks  are  often  noticeable  a  day  or  so  after  the  frost, 
and  if  badly  injured,  the  edges  continue  to  roll  back,  ex- 
posing the  bark  and  wood  to  the  weather. 

The  amount  of  cold  a  citrus  tree  will  endure  without 
injury  will  depend  upon:  (1)  the  kind  of  tree;  (2)  the 
degree  of  dormancy  of  the  tree ;  (3)  the  length  of  time  the 
cold  lasts;  and  (4)  the  kind  of  weather  following  the  cold. 
Citrus  trees  resist  frost  in  the  following  order,  beginning 
with  the  hardiest :  trifoliate,  sour  or  Seville  orange,  Sat- 
suma  mandarin  orange,  kumquat,  sweet  orange  (such  as 
the  Navel),  pomelo,  citron,  lemon,  and  lime.  In  general 
it  may  be  said  that  oranges,  if  fairly  dormant,  will  endure 
a  temperature  of  25°  or  26°  F.  for  an  hour  or  so  without 
injury.  Below  25°,  the  fruit  begins  to  freeze,  first 
that  on  the  outside  of  the  tree  and  near  the  ground,  and 
later  the  inside  fruit.  At  20  to  22°  F.,  the  twigs  begin 
to  die  back  and  the  leaves  fall,  while  a  temperature  of 
17°  or  18°  for  four  or  five  hours,  unless  the  trees  are  quite 
dormant,  will  kill  them  back  to  branches  two  or  three 
inches  in  diameter.  Lemons  are  much  more  tender,  the 
fruit  being  injured  at  26  to  28°.  The  limes  are  very 
tender,  being  killed  back  considerably  at  28  to  30°.  It 
must  be  understood  that  these  figures  are  approximate 


Frost  and  Orchard  Heating  243 

only,  a  large  number  of  variations  being  noted  in  many 
localities. 

PREVENTION    OF    FROST    INJURY 

Very  many  schemes  have  been  evolved  from  time 
to  time  for  protecting  orchards  from  frost.  Let  us 
briefly  consider  a  few  of  the  most  important. 

1.  By  selection  offrostless  or  nearly  jrostless  locations.  — 
This  plan  is  practicable  for  the  few  who  are  so  fortunate 
as  to  possess  frostless  sites.  The  great  majority  of  citrus 
orchards,  however,  are  so  situated  as  to  be  subjected  to 
occasional  low  temperatures.  It  was  pointed  out  in 
Chapter  II  that  the  best  commercial  oranges  were  pro- 
duced, not  in  tropical  climates,  but  very  near  the  frost 
line.  It  is  to  be  expected,  therefore,  that  as  the  citrus 
plantings  crowd  close  to  the  variable  and  uncertain  frost 
line,  that  the  frost  problem  will  always  be  with  us. 

2.  By  planting  resistant  varieties  or  grafting  on  resistant 
root-stocks.  —  As  a  rule,  oranges  are  planted  in  the  colder 
spots  and  lemons  in  the  warmer,  but  as  has  been  pointed 
out,  in  time  of  blizzards  the  lines  established  by  gravity- 
frosts  are  blotted  out  and  all  the  orchards  may  experience 
low  temperatures.  Much  has  been  written  in  Florida 
about  the  extra  hardiness  gained  through  the  use  of 
the  trifoliate  root-stock.  Whatever  may  have  been  the 
experience  in  Florida,  experiments  have  shown  that  in 
California  nothing  is  to  be  gained  by  the  use  of  this 
stock.  At  the  Citrus  Experiment  Station  at  Riverside 
there  is  a  duplicate  root-stock  experiment,  one  part  of 
which  is  on  high  ground  and  the  other  on  low.  These 
trees  have  been  examined  critically  after  the  severe  frosts, 


244  Citrm  Fridt'i 

and  all  who  have  seen  them  agree  that  the  trifoliate  root 
does  not  augment  the  hardiness  of  the  scion  grown  upon  it. 

3.  By  breeding  new  frost  resistant  forms  of  citrus.  — 
Directly  after  the  Florida  freeze  of  1894-95,  Messrs. 
Webber  and  Swingle  began  experiments  in  breeding  more 
hardy  citrus  fruit.  This  was  accomplished  by  hybridizing 
the  various  edible  forms  with  the  trifoliate  orange,  and 
the  citranges  described  in  Chapter  IV  were  thus  produced. 
As  yet,  however,  none  of  these  hardy  forms  have  proven 
of  commercial  value,  they  being  used  only  for  domestic 
purposes.  Breeding  new  fruits  is  a  very  slow  process,  and 
time  alone  can  tell  what  the  final  results  may  be.  For 
the  present,  they  ofi'er  no  opportunity  to  the  commercial 
grower. 

4.  By  the  use  of  various  mechanical  devices  designed  to 
conserve  heat  by  checking  radiation.  —  Much  good  may 
be  accomplished  by  the  use  of  screens  of  various  sorts 
in  conserving  latent  heat.  Such  methods  are  well 
adapted  to  young  trees  during  gravity-frosts.  When  the 
blizzard  comes,  however,  chilling  the  earth  and  trees  and 
blowing  the  heat  out  to  sea,  there  is  but  little  latent  heat 
left  in  the  plants  to  conserve,  and  such  methods  are  entirely 
inadequate. 

The  lath  screens  used  over  seed  beds  as  described  in 
Chapter  V  not  only  temper  the  rays  of  the  sun,  but  serve 
as  a  protection  from  ordinary  frosts  as  well. 

Such  screens  have  been  tried  over  large  commercial 
groves  but  proved  too  expensive  and  cumbersome.  Sheds 
over  bearing  groves  have  been  abandoned  in  California. 

Newly  planted  trees  are  much  more  susceptible  to  frosts 
than  old  trees,  and  it  is  a  very  common  practice  to  pro- 


Frost  and  Orchard  Heating  245 

tect  them  during  the  first  two  winters  by  tying  them  up 
in  cornstalks  or  tulles. 

Cloth  screens  have  been  used  to  some  extent  over  both 
nursery  stock  and  old  groves.  The  netting  cloth  which 
is  used  over  tobacco  fields  in  Connecticut  has  been  tried 
and  found  to  give  some  protection,  although  just  how  much 
is  not  yet  definitely  determined.     Sheets  of  burlap  or  tent 


Fu;.  74.  —  Thrcc-ycar-okl  trees  protected  with  eoriistalk.s. 

cloth  may  be  used  to  advantage  in  protecting  specially 
tender  or  valuable  trees  in  dooryard  and  garden.  When 
the  cold  is  severe,  a  lighted  lantern  may  be  set  under  the 
tent. 

In  northern  Florida  it  is  a  common  practice  to  make  a 
mound  of  earth  around  young  trees  to  protect  the  bud 
union  and  prevent  the  necessity  of  having  to  rebud  the 
trees.  Under  California  conditions  this  is  dangerous  on 
account  of  the  prevalence  of  the  gum-disease  organism 


246 


Citrus  Fruits 


in  the  soil.  If  trees  are  mounded  in  California,  the  trunks 
should  be  first  painted  with  bordeaux  paste  and  then 
tied  with  cornstalks  in  such  a  way  as  to  prevent  the  earth 
coming  in  contact  with  the  bark  of  the  trunk. 

5.   By  raising   the  dew-point  by  the  addition  of  water 
vapor  to  the  air.  —  This  is  accomplished  in  various  ways 


Fig.  75.  —  Screens  of  tobacco  cloth  as  a  frost  protection. 


such  as  burning  large  quantities  of  wet  straw,  distributing 
steam  among  the  trees,  filling  the  air  with  spray  such 
as  by  overhead  irrigation,  and  by  ordinary  irrigation. 
Burning  wet  straw  has  been  found  of  no  avail  for  two 
reasons.  There  is  not  enough  straw  available  in  a  coun- 
try where  every  scrap  of  organic  matter  is  needed  for 
increasing  the  humus  content  of  the  soil.  In  the  second 
place  the  air  is  so  dry  in  California  that  it  is  often  too 


Frost  and  Orchard  Heating 


247 


big  an  undertaking  to  attempt  to  raise  the  dew-point, 
especially  when  the  air  movement  carries  the  moist  air 
away  as  fast  as  produced. 

Experiments  have  actually  been  made  in  piping  steam 
from  large  boilers  and  allowing  it  to  escape  through  small 
holes  in  pipes  distributed  in  the  orchards.  This  proved 
an  entire  failure,  as  too  large  a  proportion  of  the  heat  was 
lost  through  the  smokestacks  of  the  boilers. 


Fig.  7G.  — Big  Six. 


Overhead  irrigation  has  been  tried  both  from  horizontal 
pipes  and  from  sprinklers  at  the  top  of  tall  masts.  This 
resulted  in  the  formation  of  large  masses  of  ice  on  the  trees, 
and  had  to  be  discontinued.  There  was  also  much  trouble 
from  the  freezing  and  bursthig  of  the  distributing  pipes. 

Ordinary  irrigation  has  been  found  to  raise  the  tem- 
perature from  two  to  four  degrees  above  that  of  adjacent 
nonirrigated  areas.  For  light  frosts  this  is  of  consider- 
able value,  but  is  open  to  the  following  objection.     Most 


248 


Citrus  Fruits 


citrus  growers  receive  irrigation  water  in  rotation  every 
30  (la>s,  consequently  hut  few  growers  would  have  water 
available  at  the  critical  tune.  Those  who  pump  their 
_  water  do  not  as  a 

>AtY-  --  -  ., .„;■  """v./^^r— AvJ^fc^  rule  h^ve  pumps 

of  sufficient  ca- 
pacity to  cover 
their  entire  acre- 
age at  one  time. 

Certain  grow- 
ers at  Riverside 
once  made  an  ex- 
periment of  heat- 
ing the  irrigation 
water  by  passing 
it  through  a  boiler. 
This  was  finally 
abandoned  as  too 
much  heat  was 
wasted  through 
the  smokestack. 

0.  By  viixiug 
the  air  by  creating 
artificial  wind.  — 
This  has  been  ac- 
complished in  California  in  two  ways.  By  drawing 
a  wagon  about  through  the  orchard  bearing  a  huge 
rotary  fan  driven  by  a  gas  engine ;  and  by  building 
large  bonfires  at  certain  points  which  create  a  slight 
draught.  Both  methods  have  been  abandoned  as  inade- 
quate in  the  event  of  a  sharp  frost. 


Fig.  77.  — Eichoff  Coal  Burner. 


Frost  and  Orchard  Heating  249 

7.  By  causing  frozen,  plants  to  thaw  out  slowly.  —  If  all 
frosted  fruit  could  be  picked  before  it  had  thawed  out  and 
placed  in  storage  where  it  could  thaw  gradually,  a  large 
proportion  might  be  saved.     Unfortunately,  there  is  no 


Fig.  78.  —  Hamilton  Down  Draught. 

time  to  pick  it,  and  there  are  no  houses  big  enough  to 
hold  it.  Some  growers  build  fires  of  wet  straw  and 
manure  on  the  windward  side  of  the  orchards  and  attempt 
to  keep  a  blanket  of  smoke  over  the  orchard  all  of  the 


250 


Citrus  Fruits 


morning  succeeding  the  frost  for  the  purpose  of  keeping 
the  trees  shaded  and  allowing  them  to  thaw  slowly. 
In  some  cases  this  has  apparently  been  quite  suc- 
cessful. 

8.  By  the  direct  addition  of  heat  to  the  ylants  and  the  air 
surrounding  them.  —  This  has  been  accomplished  by  burn- 
ing wood  fires  in  the  orchards,  by  burning  coal  in  wire 
baskets,  by  burning  smudge  fuel 
(shavings  and  tar),  by  suspending 
electric  heaters  in  each  tree,  and 
by  burning  crude  oil  or  low-grade 
distillate  in  some  form  of  sheet 
iron  receptacle.  Coal  is  too  scarce 
and  expensive  at  ten  dollars  a 
ton  when  compared  with  oil  at 
two  cents  a  gallon.  Smudge  fuel 
is  unsatisfactory  on  account  of 
the  smoke  and  the  scarcity  of 
the  material.  Electric  heaters 
are  clean  and  efficient  but  too 
expensive  to  install.  There  is  not 
sufficient  electric  current  available 
to  heat  more  than  an  extremely 
small  proportion  of  the  orchards. 
Several  experiments  were  carried  on  with  small  electric 
heaters  hung  in  the  trees  of  the  National  Orange  Com- 
pany's Ranch  in  southern  California  during  the  winter  of 
1912-13.  About  one  horse  power  of  electric  energy  was 
used  per  tree  during  the  cold  period.  A  thermometer,  the 
bulb  of  which  was  embedded  in  an  orange  on  the  exterior 
of  a  heated  tree,  showed  a   temperature   T   F.    higher 


Fig.  79.  — Bolton. 


Frost  and  Orchard  Heating 


251 


Fig.  80.  —  Coe. 


than  a  similarly  placed  instrument  on  an  unheated  tree. 
The  fruit  on  the  inside  of  an  unheated  tree  would  prob- 
ably have  shown  a  much  higher  temperature.  In  a  letter 
from  II.  B.  Chase,  who  conducted  the  experiments,  it  is 
stated  that  the  tem- 
perature of  the  air  in 
the  orchard  showed  no 
appreciable  increase, 
but  the  trees  and  fruit 
came  through  in  much 
better  shape  than  the 
trees  which  were  not 

heated.  The  only  conclusion  to  be  drawn  from  this 
is  that  all  of  the  heat  given  off  by  the  electric  heater 
is  radiant  heat  which  passes  through  the  air  without 
heating  it  and  is  absorbed  by  the  limbs,  foliage,  and  fruit. 
The  great  advantage  of  such  a  heater  over  the  oil  or  coal 

heater  at  once  becomes 
evident.  With  the 
electric  heater  the  heat 
given  off  practically  all 
gets  to  the  place  where 
it  is  needed,  while  with 
the  other  forms  of  heat 
generators  which  are 
placed  in  the  rows  be- 
tween the  trees,  the 
heat  given  off  (largely 
convectional  heat)  is  carried  up  above  the  trees  to  a 
great  extent  and  therefore  lost. 

Electric  heating  on  a  large  scale  is  apparently  out  of 


Fig.  81.  —  Pomona  Pipe-Line  Heater. 


252  Citrm  Fruits 

the  question  because  of  tlie  lack  of  sufficient  current  to 
serve  the  orchards  as  a  whole.  It  would  seem  a  pity, 
however,  if  a  few  conveniently  located  orchards  might 
not  be  able  to  take  advantage  of  idle  dynamos  during 
early  morning  hours  when  street  cars  and  factories  are 
not  running. 

With  the  development  of  enormous  quantities  of  very 
cheap  oil  in  California,  the  oil  burning  orchard  heater  has 
})roved  itself  eminently  practicable  and  is  now  almost 
universally  used  throughout  the  citrus  districts. 

ORCHARD  HEATING  WITH  OIL 

In  the  early  nineties,  when  the  oil  production  of  southern 
California  was  rapidly  increasing,  Charles  Froude  intro- 
duced the  first  oil  heater.  This  heater  was  later  im- 
proved by  J.  P.  Bolton  of  Fresno,  California,  formerly 
U.  S.  AYeather  Bureau  Observer  at  that  place.  The  frosts 
of  December,  1895,  in  southern  California  brought  about 
a  greatly  increased  interest  in  frost  prevention  devices. 
In  this  month  the  Riverside  Horticultural  Club  in  co- 
operation with  the  U.  S.  Weather  Bureau,  made  a  num- 
ber of  tests  of  smudging  devices,  heaters,  and  vaporizers, 
and  published  the  results  of  the  experiments.  It  was 
decided  then  that  coal  burned  in  wire  baskets,  as  described 
by  Edward  Copley,^  was  the  most  satisfactory  method. 
Since  this  time,  however,  on  account  of  the  tremendous 
development  of  oil  wells  in  and  near  the  citrus  districts, 
oil  as  a  fuel  has  become  cheaper  and  more  popular  from 
year  to  year. 

^  Riverside  Press  and  Horticulturist,  April,  189G. 


Fro.st  (i)til  Orrlidrd  Ilnttiiuj  2oA 

Requiroiiciits  of  Orchanl  llnitcrs 

The  ideal  oil  heater  should  provide  ji;o()d  conihiistioii 
and  be  as  nearly  smoke  free  as  possible.  It  should  be 
substantial  yet  simple  in  construction  and  of  anijjle 
capacity.  The  rate  of  combustion  should  be  easily 
controlled  and  it  is  an  advantage  to  have  the  parts 
nest  well  for  storage.  The  covers  must  effectually 
prevent  rainwater  from  entering.  Ease  of  handling, 
filling,  lighting,  extinguishing,  and  efficiency  of  radiation 
are  all  important.  The  cost  should  be  low,  usually 
not  above  $1  each. 

The  combustion  should  be  good,  not  only  to  obtain 
as  many  heat  units  as  possible  from  a  given  quantity 
of  oil,  but  to  lessen  the  amount  of  soot  given  off.  The 
old  idea  of  smudging  was  to  give  off  as  much  smoke 
or  smudge  as  possible  in  order  to  reduce  loss  of  heat 
by  radiation  from  the  earth.  While  this  may  have  been 
satisfactory  to  deciduous  fruit  growers  when  used  at 
blossoming  time,  it  is  a  positive  detriment  to  bearing 
citrus  orchards.  The  soot  collects  on  the  mature  fruit 
and  necessitates  rather  expensive  special  washing.  While 
smoke  in  an  orchard  does  conserve  some  heat,  citrus 
growers  would  be  glad  to  furnish  a  little  more  fuel  to 
make  up  the  loss  by  radiation  if  they  could  dispense 
with  the  soot-laden  smoke.  Most  manufacturers  ad- 
vertise smokeless  heaters,  but  few  of  them  as  yet  ap- 
proach smokelessness,  and  at  the  present  time  none  of 
the  cheaper  oil  burners  are  entirely  satisfactory  in  this 
regard,  although  marked  progress  has  been  made  toward 
this  end. 


254 


Citnis  Fruits 


Good  combustion  is  also  important  when  low  grade  oils 
carrying  a  large  amount  of  asphaltum  are  used.  Many 
heaters  will  not  burn  out  clean  with  such  oil.     A  cake  of 

gummy  material  is  left 
in  the  bottom  of  the 
heater  which  is  very 
difficult  to  remove, 
and  soon  the  capacity 
of  the  heater  is  much 
reduced. 

Heaters  should  be 
as  simple  as  possible, 
for  all  classes  of  labor- 
ers will  be  required  to 
operate  them  in  the 
cold,  dark  nights. 
The  less  joints,  valves, 
and  attachments  a 
heater  has  the  better. 
Ample  capacity  is 
important.  One  gal- 
lon heaters  have  been 
largely  discarded  in 
favor  of  the  three  and 
five  gallon  sizes.  The 
capacity  should  be  suf- 
ficient for  a  heater  to  burn  at  least  eight  hours  without 
refilling.  If  small  heaters  are  used,  a  large  number  will 
be  required,  and  this  increases  the  labor  of  handling  and 
operating. 

It  is  important  that  heaters  be  fitted  with  some  device 


Fig.  82.  —  Dunn. 


Frost  and  Orchard  Ileatim 


255 


for  controlling  the  rate  of  combustion.  This  not  only 
permits  conservation  of  fuel,  but  adds  a  great  element 
of  safety  inasmuch  as 
the  oil  saved  in  the 
early  part  of  the  night 
may  be  sorely  needed 
at  some  critical  time 
in  the  early  morning. 

Some  heaters  when 
burning  low  are  apt 
to  accumulate  gas  and 
explode,  throwing  oil 
over  the  trees  and  in- 
juring them  and  less- 
ening the  safety  of 
the  operators. 

The  heating  equip- 
ment of  citrus  orchards 
remains  in  position  all 
winter,  which  is  the 
rainy  season  in  Cali- 
fornia. If  not  well 
protected  from  rain, 
water  will  find  its  way 
into  the  oil  and  sink 
to  the  bottom.  When 
the  oil  is  lighted  this 
water  turns  to  steam 
and  causes  the  heaters 
to  boil  over.  This  results  in  a  temporary  bonfire  which 
soon  burns  out  and  leaves  the  trees  unprotected. 


Fig.  83.— Canco. 


256 


Ciirus  Fruits 


The    f^reater    the    j)r()})()rti()n    of    radiated,    and    the 
less    convectional    lieat    <:;iveii    off    by    any    heater    the 
greater  its  efficiency.     Tliis  important  principle  is  often 
JSlli__-jM  overlooked  whUe  con- 

sidernig  ponits  appar- 
ently more  practical. 
The  Indians  of  Peru 
are  said  to  have  used 
for  centuries,  in  pro- 
tecting their  crops 
from  "  gravity  "  spring 
frosts,  a  heavy  clay 
pot  in  which  char- 
coal is  burned.  By 
this  means  they  se- 
cured radiated  heat 
almost  exclusively. 

From  a  considera- 
tion of  the  above  re- 
quirements it  will  be 
seen  that  the  develop- 
ment of  a  thoroughly 
practical  and  efficient 
oil  heater  is  not  an 
easy  matter.  Four  or 
five    of    the    require- 


FiG.  84.  —  Rayo. 


ments  may  be  combined  without  much  difficulty,  but 
some  are  more  or  less  conflicting.  It  is  especially  diffi- 
cult to  combine  perfect  combustion  and  control  of 
combustion  with  simplicity  and  cheapness. 


Frost  ami  Orchard  Heating 


257 


Types  of  Oil  Heaters 

During  the  years  1911  to  1914  there  was  a  tremendous 
amount  of  experimentation  in  developing  types  of  heaters 
to  meet  the  require- 
ments of  citrus  growers. 
Almost  every  one,  from 
the  local  blacksmith  to 
the  Standard  Oil  Com- 
pany, seemed  to  have 
a  new  idea  and  was 
sure  that  he  could  pro- 
duce the  attachment  or 
device  which  would  put 
him  ahead  of  everybody 
else.  As  a  result,  a  very 
large  number  of  different 
heaters  were  turned  out 
and  the  patent  attorneys 
had  their  hands  full. 
Still  the  improvement 
in  heaters  goes  merrily 
on.  We  cannot  under- 
take a  detailed  descrip- 
tion of  all  these  different 
heaters,  as  lack  of  space 
forbids,  and  no  doubt 
they  will  all  be  changed 
more  or  less  during  the 
next  few  years.  The  ac- 
companying sketches 

8 


Fig.  85. 


258 


Citrus  Fruits 


Fig.  86.  —  Hamilton  Reservoir. 

grouped  into  three  general  classes 
heaters ;  (6)  automatic  reser- 
voir heaters;  (c)  pipe-line 
heaters.  Simple  reservoir  heat- 
ers are  the  kind  ordinarily  used 
which  burn  from  a  free  surface 
and  are  adapted  to  low-grade 
oil.  Automatic  reservoir  lieat- 
ers  have  a  patent  burner  sepa- 
rate and  several  feet  distant 
from  the  tank.  The  high- 
grade  oil  used  is  fed  by  a 
small  iron  pipe  which  passes 
through  the  almost  smokeless 
flame,  the  oil  being  volatilized 
as  it  is  fed.  The  burner  is 
inclosed  in  a  sheet  iron  pipe 
or  drum,  which  acts  as  a  radi- 
ator. This  type  has  great  pos- 
sibilities, but  is  rather  expen- 
sive and  cumbersome. 

Pipe-line  heaters  are  fed  through 
set  above  the  orchard.     There  are 


and  pictures  of  heat- 
ers installed  in  or- 
chards will  suffice  to 
give  a  general  idea  of 
the  leading  types  at 
this  time. 

At  present  these 
heaters  may  be 
:    (a)  simple  reservoir 


Troutnian. 


pipes  from  a  large  tank 
several  forms,  some  of 


Frost  and  Orchard  Heating 


259 


which  burn  the  oil  by  dropping  it  slowly  into  a  super- 
heated cast  iron  bowl.  Others  require  the  orchard  to  be 
piped  with  compressed  air  as  well  as  oil,  and  the  oil  is 
finely  atomized  in  the  burner  and  driven  with  some  force 
into  the  drum,  where  it  burns.  The  great  objection  to 
these  forms  is  the  expense  of  piping  the  orchard,  yet  there 
is  much  in  their  favor.  The  rate  of  combustion  of  all 
the  heaters  in  the  orchard  may  be  controlled  by  operating 
one  valve  at  the  tank,  and  much  of  the  annual  expense  of 
handling  and  loss  from  deterioration  of  reservoir  heaters 
is  eliminated. 

Installation  of  Heaters 

The  number  of  heaters  required  to 
the  acre  varies  of  course  with  the  size 
and  variety  of  trees  and  the  degree 
of  cold  to  be  encountered.  A  fairly 
common  equipment  consists  of  one 
three  gallon  heater  to  a  tree,  which 
is  usually  about  ninety  to  the  acre. 
These  should  be  reenforced  by  an 
extra  row  around  the  windward  side 
of  the  orchard.  With  such  an  equip- 
ment it  should  be  possible  to  raise 
the  temperature  from  seven  to  ten 
degrees  for  from  seven  to  ten  hours, 
depending  on  wind  and  other  factors. 
Some  growers  use  double  this  number 
and  light  only  every  alternate  heater 
during  the  early  part  of  the  night, 


88.  —  Adamson 
Torch. 


260  Citrm  Fruits 

holding  the  others  as  a  reserve  to  be  Hghted  only  in  case 
of  emergency. 

It  has  been  found  much  better  to  have  many  small 
fires  than  a  few  large  ones,  as  large  fires  tend  to  create 
convectional  currents  which  carry  much  of  the  heat  far 
above  the  tops  of  the  trees.  There  is  also  danger  of  in- 
juring the  trees  with  large  fires.  As  stated  above,  one 
heater  per  tree  has  been  found  to  be  the  best  plan. 

The  heaters  are  placed  on  the  ground  midway  between 
the  trees  and  in  line  with  the  trees  in  one  direction.  If 
placed  in  the  center  of  the  square  made  by  four  trees, 
they  will  be  in  the  way  of  the  wagons  which  haul  the  fruit 
out  and  the  oil  and  manure  into  the  orchards. 

Properties  of  Fuel  Oils 

Petroleum  when  first  taken  from  the  wells  is  rich  in 
gases  and  lighter  substances  such  as  benzine,  gasoline,  and 
kerosene.  Besides  these,  it  also  contains  such  basic  sub- 
stances as  asphaltum  and  paraffine.  The  crude  oils  of 
the  Eastern  states  have  chiefly  a  paraffine  base,  while 
nearly  all  Pacific  Coast  oils  have  an  asphaltum  base. 
The  fuel  oils  on  the  market  are  residuals,  the  gasoline  and 
other  lighter  oils  for  which  there  is  a  large  demand  having 
been  removed  in  the  refining  process.  What  is  known  as 
crude  oil  is  not  petroleum  as  it  comes  from  the  wells,  but 
a  refinery  residuum  containing  some  of  the  heavy  oils,  a 
variable  amount  of  asphaltum,  together  with  some  sul- 
fur and  a  little  water. 

The  types  of  oil  commonly  used  are  the  so-called  crude 
oil,  smudge  oil,  slop  distillate,  and  stove  distillate.     A 


Frost  and  Orchard  Heating 


261 


particular  <frade  of  oil  is  usually  recomuiended  for  each 
type  of  heater.  A  jijood  grade  of  oil  fairly  free  from 
asphaltum,  such  as  20  gravity  sloj)  distillate  for  instance, 
costs  about  two  cents  per  gallon  in  carload  lots  delivered 
on  siding  in  southern  California  citrus  districts.  The 
cars  vary  in  capacity  from  GOOO  gallons  minimum  to  12,000 


Fig.  89. 


■  Coal  burning  orchard  heaters, 
trees. 


Fuel  stored  in  boxes  under 


gallons  maximum.  One  great  advantage  in  this  oil  as  a 
fuel  is  its  availability  in  very  large  quantities.  During 
the  blizzard  of  January,  1913,  trainloads  were  ordered  by 
telephone  one  day,  and  the  oil  was  dispatched  in  trains 
having  right-of-way,  and  was  delivered,  and  in  some 
instances  was  actually  gotten  into  the  heaters  and  fired 
before  daylight  next  morning. 

The  density  of    the  fuel  oils  varies    from   14  degrees 


262  Citrus  Fruits 

Baume  to  35  degrees  or  more.  Specific  gravity  varies 
from  .850  or  less  to  as  lieavy  as  .975.  The  heating  vahie 
is  usually  stated  in  British  Thermal  Units,  and  varies 
from  17,500  to  19,100  B.  T.  U.  a  pound. 


Fig.  90.  —  Orchard  heaters  ready  for  lighting. 

Lighter  oils  are  preferred  when  they  are  to  be  pumped 
or  delivered  through  pipe-lines  for  the  reason  that  in 
cold  weather  heavy  oils  become  thick  and  sluggish  like 
molasses  and  are  very  difficult  to  handle  in  small  pipes. 

Storage  for  Oil 

As  freezing  temperatures  often  occur  several  nights  in 
succession,  it  is  highly  desirable  to  have  an  adequate 
means  of  storing  the  oil  on  the  ranch  near  the  trees.  Stor- 
age capacity  should  be  provided  for  at  least  five  fillings 
of  all  the  heaters  on  the  ranch. 


Frost  and  Orchard  Heating 


263 


Cement  cisterns  have  been  used  to  some  extent  for  oil 
storage,  but  are  often  unsatisfactory.  At  present,  gal- 
vanized circular  iron  tanks,  similar  to  those  used  by  the 
oil  companies,  are  chiefly  used. 

Oil  storage  tanks  should  be  located  if  possible  on  a  side 


Fig.  91.  —  Orchard  heaters  in  old  Valencia  grove. 


hill  in  order  that  they  may  be  filled  by  gravity  from 
above,  and  the  oil  (leli\ered  by  gravity  to  the  distributing 
wagons  below. 

On  a  number  of  the  larger  ranches  it  has  been  found 
expedient  to  install  small  tanks  in  various  parts  of  the 
orchards  and  connect  them  with  the  large  ele\ated  tanks 
by  a  system  of  pipe-lines.     The  Arlington  Heights  Fruit 


264  Citrus  Fruib 

Company  at  Uiverside  Jias  a  main  steel  storajje  tank  of 
500,000  gallons  capacity  connected  with  a  ()-incli  i)ip(>-line 
five  and  one-half  miles'lonj;,  which  serves  ten  smaller  tanks 
each  of  12,000  <]fallons  capacity.  At  intervals  through  the 
orchard  there  are  "gooseneck"  stand  pipes  from  which 
the  wagons  may  be  filled.  The  Limoneira  orchard  at 
Santa  Paula  is  equipped  with  two  steel  tanks  holding 
210,000  gallons  each  and  two  cement  cisterns  holding 
100,000  gallons  each.  This  5()0-acre  orchard  has  five 
miles  of  3-  and  4-inch  pipe-line  and  four  miles  of  telephone 
line  with  a  dozen  or  more  telephones  located  in  various 
parts  of  the  orchard.  Thirty-five  tank  wagons  and 
trucks  are  used  to  distribute  the  oil  to  the  heaters. 

Oil  Heating  Operations 

For  delivery  of  oil  to  the  heaters,  tank  w^agons  of  four 
or  five  hundred  gallons  capacity  should  be  used.  Heavier 
wagons  are  difficult  to  handle  in  cultivated  or  freshly 
irrigated  soil.  The  tank  is  provided  at  the  rear  with  a 
large  valve  or  molasses  gate,  and  men  following  the  wagon 
fill  the  heaters  by  means  of  five-gallon  buckets  or  ordi- 
nary oil  cans  with  the  tops  cut  off  and  provided  with 
handles.  Filling  heaters  by  means  of  a  trailing  hose  was 
tried,  but  has  now  been  abandoned.  One  group  of  men 
go  ahead  of  the  tank  wagon  and  remove  the  covers  from 
the  heaters,  and  others  follow  and  replace  the  covers. 

Many  kinds  of  lighting  devices  have  been  tried,  but 
the  Adamson  lighter  shown  in  Fig.  78  has  come  into 
almost  universal  use.  This  is  merely  an  oil  can  in  the 
spout  of  which  a  roll  of  wire  gauze  and  asbestos  wicking 


Frost  and  Orchard  Heating  265 

has  been  loosely  fitted.  After  lighting  the  wick  and  in- 
verting the  can  over  an  open  heater  a  few  drops  of  gasoline 
or  high-grade  stove  distillate  will  pass  through  the  flame 
and  fall  burning  into  the  heater.  By  use  of  this  device 
heaters  may  be  lighted  almost  instantly.  It  is  a  peculiar 
fact  that  new  heaters  are  very  difficult  to  light  the  first 
time.     This  difficulty  is  easily  obviated  by  crowding  a 


Fig.  92.  —  Placoinent  of  orchard  heaters.     Extra  fuel  undor  trees. 

loose  wad  of  tow  or  excelsior  into  the  mouth  of  the  down- 
draught  tube  or  by  hanging  a  small  asbestos  wick  on  the 
side.  This  precaution  will  usually  not  be  necessary  after 
a  little  soot  has  accumulated  in  the  heater. 

It  is  the  custom  to  begin  firing  lemons  when  the  tem- 
perature at  three  feet  from  the  ground  reaches  30°  F. 
A  safe  plan  is  to  watch  the  young  leaves  on  the  lower 
part  of  the  trees  and  begin  firing  as  soon  as  they  show 
transparent    spots    indicating    that    they    are    freezing. 


266 


Citrus  Fruits 


Oranges  may  be  allowed  to  go  several  degrees  lower 
because  they  do  not  carry  blossoms  and  tender  young 
fruit  in  winter  as  the  lemon  does.     It  has  been  found 

that  it  is  much  easier 
to  hold  the  tempera- 
ture at  32°  than  it  is 
to  raise  it  to  32°  again 
once  it  has  fallen  lower. 
Many  growers  make 
a  practice  of  lighting 
only  every  alternate 
pot  at  first,  holding  the 
others  in  reser\'e  to  be 
lighted  later  if  needed. 
In  case  heavy  firing 
and  refilling  becomes 
necessary  it  sometimes 
is  confusing  for  the 
workmen  to  tell  at  a 
glance  w'hich  heaters 
were  lighted  first. 
This  difficulty  may  be 
obviated  by  painting 
a  ring  with  white  paint 
on  every  alternate  pot 
in  the  rows.  It  also 
saves  about  one-third 
of  the  labor  of  lighting  alternate  pots  to  work  diagonally 
through  the  orchard  when  the  trees  are  planted  in  squares. 
It  often  happens  that  the  temperature  will  not  go  below 
32  degrees  before  four  or  five  o'clock  in  the  morning,  and 


Fig.  93.  —  The  perforated  stack  gives 
good  combustion  but  may  admit  rain- 
water. 


Frost  and  Orchard  Heating  267 

it  will  be  necessary  to  fire  only  a  few  hours.  This  usually 
pays  well,  however,  for  the  blossoms  and  young  fruit 
which  are  on  the  trees  during  winter  mature  in  late 
summer  when  the  prices  are  highest.  As  soon  as  the 
sun  rises  or  the  wind  begins  to  blow  the  temperature 
rises  and  the  heaters  may  be  extinguished  and  the  oil 
conserved  for  future  needs. 

Heaters  may  be  extinguished  by  replacing  the  covers. 
Occasionally  on  very  cold  nights  it  may  be  necessary  to 
refill  the  heater  during  firing  operations.  This  is  accom- 
plished by  placing  the  cover  on  for  a  few  moments  until 
the  fire  is  out  and  then  refilling  and  relighting. 

During  the  winter  1912-13  one  orchardist  fired  his 
lemon  orchard  on  twenty-nine  nights  and  saved  enough 
fruit  to  pay  for  his  heating  equipment  and  all  the  expense 
of  firing. 

Care  of  Heaters 

The  depreciation  of  orchard  heaters  is  heavy,  especially 
with  the  cheaper  forms.  Being  exposed  to  winter  rains, 
they  rust  badly  unless  well  cared  for.  It  is  usual  to 
charge  off  from  15  to  25  per  cent  depreciation  for  each 
year  of  service.  In  the  spring  when  danger  of  frost  is 
past  the  heaters  are  emptied  into  the  tank  w^agons,  the 
oil  being  returned  to  the  storage  tanks.  Each  heater  is 
then  dipped  in  asphaltum  paint  made  by  melting  asphal- 
tum  and  diluting  it  with  one  gallon  of  stove  distillate  to 
ten  pounds  of  asphaltum.  Some  growers  even  repaint 
the  heaters  in  the  orchard  after  a  siege  of  firing  has  burned 
the  paint  off.  It  is  extremely  wasteful  to  store  the 
heaters  over  summer  in  a  rusty  condition.     In  storing  the 


268  Citrus  Fruits 

heaters  it  will  be  found  that  those  whose  parts  nest  well 
are  much  more  economical  of  space.  At  present  some 
grower^;  store  the  oil-filled  pots  under  the  trees  in  order 
to  save  expense  of  handling.  This  is  satisfactory  pro- 
vided they  are  well  i)ainted.  One  trouble  has  been  chat 
careless  laborers  while  hoeing  under  the  trees  are  apt  to 
strike  the  pots  with  hoes  and  cut  small  holes  through 
which  the  oil  leaks,  soaking  the  soil  and  killing  the  trees. 

Cost  of  Oil  Heating 

While  the  cost  of  heating  varies  widely  and  is  in  some 
cases  high,  there  is  no  doubt  in  the  minds  of  those  who 
have  the  most  experience  that  orchard  heating  pays  well, 
especially  for  lemons. 

Two  typical  actual  expense  accounts  are  given  below, 
one  for  a  small  grove  and  one  for  a  large  ranch.  In  both 
cases  the  figures  are  for  1912-13. 

Richardson    Brothers'     Lemon     Orchard,    Duarte,     Cali- 
fornia. ^     Fourteen  Acres — ^1000  Trees 

Equipment 

.500  Hamilton  heaters,  3  gal $200.00 

700  Bolton  heaters,  2  gal 154.00 

Tank  wagon,  463  gal.  capacity 48.00 

Cement  cistern,  8500  gal.  capacity 125.00 

Oil  buckets  3,  lighters  2         6.25 

Four  thermometers  and  automatic  alarm    ....  40.00 

Total  for  equipment $573.25 

Oil  and  labor 

Oil  for  16  nights,  16,195  gallons $437.26 

Labor  bill  for  same 201.50 

Total  expense  for  operation $638.76 

1  California  Cultivator,  Feb.  27,  1913,  p.  260. 


Frost  and  Orchard  Heating  2G9 


LiMONEiRA    Orchard    Company,    Santa    Paula,    California. 
Five  Hundred  Acres  ^ 

50,000  oil  heaters  (including  a  thousand  of  last  year's 

pots) $50,000.00 

2  steel  storage  tanks,  capacity  210,000  gallons  each  4,885.89 

2  cement  reservoirs,  capacity  100,000  gallons  each  3,000.00 

5  miles  of  3-inch  and  4-inch  pipe-Hne      ....  6,375.03 
35  tank  wagons  and  trucks 4,315.00 

150  spout  pails  for  filling  pots        300.00 

200  torches 200.00 

50  thermometers        150.00 

4  miles  of  telephone  system        750.00 

350,000  gallons  of  oil  in  orchard  at  2\  cents    .     .     .  8,750.00 

500,000  gallons  of  oil  in  storage  at  2\  cents     .     .     .  12, .500. 00 

Total $91,225.92 

Reduced  to  the  basis  of  one  acre,  the  investment  is : 

100  heaters $100.00 

Storage  space  for  1,240  gallons  of  oil 15.77 

Pipe-hne 12.75 

One  tank  wagon  to  14  acres  —  per  acre      ....  8.63 

Pails  —  one  to  3^  acres  — per  acre          .60 

Torches  —  one  to  2^  acres  —  per  acre .40 

Thermometers  —  one  to  10  acres  —  per  acre       .     .  .30 

Telephone 1.50 

Oil  in  heaters  —  700  gallons  at  2^  cents     ....  17.50 

Oil  in  storage  —  100  gallons  at  2^  cents      ....  25.00 

Total $182.45 

Interest,  deterioration,  and  maintenance  : 

6  per  cent  interest  on  total  investment  — -  $10.94 
15  per  cent  deterioration  on  $100  worth  of  heaters  15.00 

6  per  cent  deterioration  on  other  equipment   .     .  2.40 

Estimated  handling,  painting,  and  filling  (no  firing)  5.00 

Total $33.34 

This  outlay  would  seem  at  first  glance  to  make  the 
expense  of  growing  lemons  under  such  conditions  pro- 

'  The   Monthly  Bulletin,  California  State  Com.  Hort.,  Vol.  3, 
No.   1,  January,   1914. 


270  Citrus  Fruits 

hibitive,  and  yet  J.  D.  Ciilbertson,  the  assistant  manager 
of  the  ranch,  states  that  all  of  this  expense  was  met  by 
the  sale  of  the  lemons  saved  and  "  fair  interest  in  dividends 
was  paid  to  stockliolders  out  of  this  year's  earnings!" 

SEPARATION  OF  FROSTED  FRUITS 

The  Board  of  Food  and  Drug  Inspection  of  the  U.  S. 
Department  of  Agriculture  made  the  following  ruling  in 
regard  to  frosted  citrus  fruits  on  January  24,  1913 : 

"  Citrus  fruit  is  injured  in  flavor  by  freezing  and  soon 
becomes  dry  and  unfit  for  food.  The  damage  is  evidenced 
at  first  by  a  more  or  less  bitter  flavor,  followed  by  a  marked 
decrease  in  sugar,  and  especially  in  acid  content.  Fruit 
which  has  been  materially  damaged  by  freezing  is  inferior 
and  decomposed  within  the  meaning  of  the  Food  and 
Drugs  Act. 

"  For  the  guidance  of  those  engaged  in  shipping  citrus 
fruit,  it  is  announced  that,  pending  further  investigation, 
the  following  principles  will  be  observed  in  enforcing  the 
Food  and  Drugs  Act : 

"Citrus  fruit  will  be  deemed  adulterated  within  the 
meaning  of  the  Food  and  Drugs  Act  if  the  contents  of 
any  package  found  in  interstate  commerce  contain  fifteen 
per  cent  or  more  of  citrus  fruit  which,  on  a  transverse 
section  through  the  center,  shows  a  marked  drying  in 
twenty  per  cent  or  more  of  the  exposed  pulp." 

There  is  much  variation  in  the  degree  of  frozen  fruit 
on  the  same  tree.  The  oranges  on  the  tops  of  tall  trees 
are  usually  less  frozen  than  those  near  the  ground.  Fruit 
on  the  inside  of  the  tree  is  less  frozen  than  that  on  the  out- 


Frost  and  Orchard  Heating 


271 


side.     Thus  when  the  fruit  is  picked  after  a  damaging 
freeze  the  good  and  bad  fruit  will  be  mixed  together.     If 


Fig.  94.  —  One  type  of  water  separator  for  frosted  oranges. 

the  grower  does  not  want  to  sell  all  his  fruit  at  a  great 
discount  as  frozen  fruit,  or  run  the  risk  of  having  trouble 


272  Citrus  Fruits 

with  Food  and  Drugs  inspectors,  lie  must  separate  the 
frozen  from  the  uninjured  fruit. 

This  is  not  as  simple  a  matter  as  would  at  first  appear 
for  the  reason  that  the  fruit  usually  presents  no  outward 
indication  of  its  interior  condition. 

Usually,  after  a  few  weeks,  frozen  fruit  loses  a  con- 
siderable proportion  of  its  moisture  and  grows  lighter  in 
weight.  Upon  this  fact  are  based  all  methods  of  separat- 
ing frozen  from  sound  fruit.  Normal  oranges  have  a 
specific  gravity  of  .82,  but  a  few  weeks  after  being  frozen 
they  dry  out  and  become  lighter.  If  oranges  are  dropped 
in  a  liquid  the  specific  gravity  of  which  is  slightly  lower 
than  that  of  good  fruit,  the  sound  fruit  will  sink  while 
the  frozen  fruit  will  float. 

The  first  separations  made  on  this  principle  were  ac- 
complished by  using  a  mixture  of  kerosene  and  distillate 
oils.  This  proved  very  objectionable  on  account  of  the 
odor  left  on  the  fruit.  D.  C.  Lefferts  of  Redlands  in- 
vented a  machine  consisting  of  a  large  trough  in  which 
denatured  alcohol  of  the  proper  specific  gravity  is  placed 
to  a  depth  of  about  thirty  inches.  The  fruit  is  carried 
by  conveyors  and  floated  in  the  alcohol.  A  double  con- 
veyor sweeps  the  surface  of  the  liquid  and  delivers  the 
frozen  fruit  to  one  belt,  while  the  returning  conveyor  drags 
on  the  bottom  and  delivers  the  sound  fruit  at  another 
point.  More  or  less  difficulty  was  encountered  by  the 
alcohol  increasing  in  specific  gravity  by  the  water  absorbed 
and  the  inability  of  redistilling  it  on  account  of  national 
laws  governing  distillation. 

After  the  Left'erts  machines  had  been  used  in  many 
packing-houses  for  two  years,  Frank  Chase  of  Riverside 


Frost  and  Orchard  Heating  273 

invented  the  water  separator,  which  quickly  displaced  all 
other  methods  of  separating  oranges.  This  machine  con- 
sists of  an  oblong  tank  through  which  water  may  be  made 
to  circulate  at  definite  speeds  by  a  small  propeller.  The 
oranges  roll  down  an  incline  and  drop  into  the  moving 
water  from  a  height  of  a  foot  or  more.  The  light  frosted 
oranges  bob  up  to  the  surface  quickly,  while  the  sound, 
heavy  fruit  is  slower  to  rise.  IMeanwhile  the  oranges 
have  been  carried  along  by  the  current,  the  sound  fruit 
passing  under,  and  being  caught  by  a  horizontal  wire 
screen,  while  the  light  fruit  is  carried  along  above  it.  At 
the  farther  end  of  the  tank  the  two  grades  are  lifted  by 
conveyors  and  delivered  to  separate  bins.  By  adjusting 
the  position  of  the  screen  and  the  rate  of  flow  of  the 
water  any  degree  of  separation  desired  may  be  secured. 
This  device  enables  the  grower  to  save  whatever  sound 
fruit  may  have  been  left,  and  he  may  ship  it  under  his 
regular  brands  with  some  assurance.  The  frosted  fruit, 
if  not  seriously  injured,  may  be  shipped  under  a  special 
frost  brand  or  it  may  be  used  as  a  fertilizer,  or  made  into 
various  by-products. 

The  water  separator  does  not  work  satisfactorily  with 
lemons  for  the  reason  that  they  are  not  round,  and  the 
depth  to  which  they  sink  in  the  water  will  depend,  to  an 
extent,  on  the  position  in  which  they  happen  to  strike 
the  surface.  For  the  separation  of  lemons  the  denatured 
alcohol  bath  is  still  used.  A  layer  of  lemons  is  placed  in  a 
large  wire  tray  and  submerged  in  the  alcohol,  which  has  8 
specific  gravity  of  .82.  The  frosted  lemons  float  and  are 
removed  by  hand.  Frequent  tests  with  the  hydrometer  are 
necessary  in  order  to  keep  the  liquid  at  the  proper  density. 

T 


274  Citrufi  Fruits 

The  question  is  often  raised  as  to  whether  fruit  whicli 
is  only  slightly  frozen  may  not  improve  and  fill  up  with 
juice  again  if  left  on  the  trees.  The  writer  has  observed 
this  to  take  place  to  a  limited  extent  both  with  lemoiLs 
and  Valencia  oranges.  It  appears  that  the  individual 
juice  vesicles  in  any  particular  fruit  vary  in  their  resist- 
ance to  freezing.  Some  reabsorb  the  water  which  has 
been  drawn  out  of  the  cells  in  order  to  crystallize,  while 
others  fail  to  do  so  and  collapse.  A  juice  vesicle  once 
collapsed  apparently  will  not  fill  up  with  juice  again, 
although  the  cells  making  up  the  walls  may  retain  life. 
Those  juice  vesicles  which  do  regain  their  turgidity,  how- 
ever, will  grow  larger  than  they  otherwise  would  and  to 
an  extent  will  fill  up  the  spaces  left  by  the  collapsed  cells. 
When  more  than  one-half  the  number  of  vesicles  are  de- 
stroyed, the  gain  in  size  of  the  others  will  hardly  be  suffi- 
cient to  make  the  fruit  marketable.     See  Fig.  72. 

COOPERATION    IN    FROST    FIGHTING 

The  large  citrus  ranches  are  in  a  measure  sufficient  unto 
themselves  when  frost  fighting  is  undertaken.  On  account 
of  their  size  and  the  large  number  of  men  employed  they 
are  able  to  organize  their  forces  effectively.  The  interests 
of  small  growers,  however,  who  own  three,  five,  or  ten 
acres  each  will  be  best  served  through  cooperation  wherever 
their  holdings  lie  close  together.  For  some  years  a  very 
successful  organization  of  this  kind  has  operated  at 
Pomona.  It  is  known  as  the  Pomona  Valley  Orchard 
Protection  Association  and  is  composed  of  many  small 
growers  of  the  district  who  own  in  the  aggregate  about 


Frovt  and  Orchard  Hcatittg 


275 


3000  acres.  Supplies  are  bought  by  wholesale,  and  the 
labor  of  firing  is  carried  on  by  a  specially  organized  force 
which  is  directed  by  one  manager  by  telephone  from  a 
central  station. 

Thermometer  stations  are  located  at  convenient  points 
along  the  roads  running  through  the  orchards,  and  scouts 
mounted  on  motor- 
cycles make  the 
rounds  of  these  sta- 
tions on  nights  when 
danger  from  frost  is 
imminent.  The  tem- 
peratures are  reported 
to  the  manager  at  the 
central  office;  and 
when  the  tempera- 
tures fall  dangerously 
low  in  any  section,  the 
owners  of  the  orchards 
in  that  district  are 
notified  by  telephone 
to  prepare  for  lighting 
their  heaters.  As 
these  temperature  rec- 
ords are  all  charted  and  preserved,  they  constitute  a 
fund  of  information  in  regard  to  air  currents  and  cold 
spots  which  is  of  very  great  practical  value  in  all 
future  operations.  The  example  set  by  this  organiza- 
tion should  be  followed  in  other  districts  where  many 
small  orchards  lie  near  together. 

In  concluding  this  chapter  we  may  say  that  whatever 


Fig.  95.  —  Thermometer  station  of  Pomonn 
Valley  Orchard  Protection  Association. 


276  CltrtLs  Fruits 

may  have  been  the  final  verdict  in  regard  to  deciduous 
orchard  heating  in  intermountain  states,  the  heating  of 
citrus  orchards  in  Cahfornia  has  proved  a  decided  success, 
and  new  heaters  are  being  installed  as  fast  as  the  factories 
can  turn  them  out.  It  is  safe  to  say  that  citrus  and 
especially  lemon  orchard  heating  in  California  has  come 
to  stay  —  at  least  as  long  as  cheap  fuel  oil  is  available. 
Judging  from  the  present  increase  in  oil  production  in  the 
state  there  would  appear  to  be  no  warrant  for  any  un- 
easiness in  regard  to  the  fuel  supply  for  many  years  to 
come. 


CHAPTER  XV 
PICKIXG  AND  PACKING  ORANGES 

California  oranges  are  harvested  throughout  the  year. 
Navel  oranges  are  picked  from  November  1  to  May  1. 
Occasionally  Navel  picking  continues  till  June.  Most 
seedlings  and  miscellaneous  varieties  such  as  Mediter- 
ranean Sweet,  Paper  Rind  St.  INIichael,  Ruby  and  jNIalta 
Blood,  and  Crafton  are  picked  during  May  and  early  June. 
Valencias  are  harvested  from  June  1  to  November  1  or 
later,  thus  o\erlapping  the  next  Navel  crop. 

Oranges  are  picked  with  a  great  deal  of  care  for  the 
reason  that  carelessness  will  result  in  bruises  and  abrasions 
of  the  skin  which  admit  the  germs  of  decay.  An  orange 
with  a  perfectly  sound  skin  is  proof  against  decay  and  will 
normally  live  and  respire  (breathe)  for  several  months, 
gradually  losing  water  and  carbon  dioxide  until  it  finally 
dries  up,  turns  brown,  and  becomes  as  hard  as  a  wooden 
ball.  Oranges  will  not  rot  unless  they  become  infected 
with  microscopic  plants  which  grow  in  the  tissue,  softening 
and  breaking  it  down.  All  such  premature  decays  (and 
there  are  many  kinds)  are  preventable. 

As  before  stated,  the   unbroken,  healthy  skin  of  the 

orange  is  proof  against  almost  all  such  decays ;  but  when 

the  skin  is  abraded  in  any  way,  these  germs  are  almost 

sure  to  get  in,  as  the  air  is  full  of  them,  and  most  ordinary 

277 


278  Citrus  Fruits 

objects,  such  as  gloves,  bags,  boxes,  and  the  hke,  are 
always  coated  with  them.  The  reader  should  remember 
that  these  germs  or  spores  are  practically  ever  present, 
and  he  has  only  to  blow  his  breath  across  a  moldy  orange 
or  lemon  and  observe  the  billions  of  minute  "seeds"  or 
spores  floating  in  a  cloud,  to  realize  the  enormous  number 
produced.  If  some  of  this  "mold  dust"  be  examined 
under  a  microscope,  each  particle  will  be  found  to  be  a 
well-developed  spore  capable  of  reproducing  the  same 
decay  whenever  it  may  fall  in  a  suitable  place  to  grow. 

Sometimes  in  dry  weather  a  very  slight  scratch,  which 
breaks  the  oil  cells  only,  is  cauterized  over  and  healed 
without  infection  taking  place,  but  this  is  not  always  the 
case  and  it  rarely  happens  in  damp  weather. 

When  the  fruit  is  hanging  on  the  tree  the  rind  is  filled 
with  water  and  the  surface  cells  are  turgid.  They  are 
very  easily  broken  when  in  this  condition,  while  after  the 
fruit  has  been  stored  in  the  packing-house  a  few  days 
and  the  rind  dried  out  somewhat  the  fruit  will  endure  a 
great  deal  more  in  the  way  of  rough  handling.  This  is 
the  reason  why  it  is  wise  to  let  the  fruit  cure  on  the 
packing-house  floor  for  a  few  days  before  running  it 
through  the  various  machines. 

The  following  are  a  few  of  the  ways  that  abrasions  may 
occur,  and  each  of  these  should  be  carefully  watched : 

a.  Clipper-cutting ;  careless  pickers  often  allow  the 
points  of  the  clippers  to  extend  beyond  the  stem  and  cut 
into  or  prick  the  skin. 

b.  Stem  punctures ;  all  stems  must  be  cut  oft'  short 
and  smooth,  else  they  will  be  sure  to  puncture  the  skins 
of  other  oranges  during  handling. 


Picking  and  Packing  Oranges  279 

c.  Fingernail  scratches ;  all  pickers  should  be  required 
to  wear  soft  cotton  gloves  which  are  made  especially  for 
the  purpose  and  sold  for  from  60  to  85  cents  a  dozen 
pairs. 

d.  Gravel  scratches ;  sometimes  a  careless  workman 
will  throw  an  empty  box  from  the  distributing  wagon  in 
such  a  way  that  sand  or  gravel  will  be  flirted  into  it. 
Before  filling  a  field  box  it  should  always  be  inverted  and 
the  bottom  tapped  to  dislodge  any  grain  of  sand  present. 

e.  Nails  in  boxes  ;  in  many  cases  nails  have  been  found 
protruding  on  the  inside  of  field  boxes,  and  their  points 
rusted  by  pricking  into  perfectly  good  oranges. 

/.  Thorn  scratched  and  dropt  fruit ;  often  with  thorny 
varieties  considerable  care  is  needed  to  extricate  interior 
fruit  from  the  brush  ^^^thout  scratching  it.  No  fruit 
which  is  dropped  should  be  picked  up,  as  it  is  almost  sure 
to  decav. 


Fiu.  96.  —  Tuttle  fruit  clippers  with  rounded  point 


The  clippers  now  used  are  a  great  improvement  over 
the  old  styles.  They  have  rounded  points,  and  in  certain 
types,  cup-shaped  blades.  JMost  fruit  should  be  double 
clipped,  that  is,  the  fruit  is  separated  from  the  branch 


280 


Citrus  Fruits 


with  one  motion,  and  then  held  in  a  more  convenient 
position  while  the  stem  is  carefully  cut  off  short  and 
smooth.  The  green  calyx  or  "  button"  should  always  be 
left  on  the  fruit,  for  if  it  is  pulled  off,  an  opening  is  made 
for  the  entrance  of  decay  germs. 

Only  cloth  picking  bags  are 
used,  of  which  there  are  five 
or  more  types.  They  are  car- 
ried by  a  broad  strap  which 
passes  over  the  shoulder,  and 
the  most  approved  types  are 
adjustable  in  capacity  and  open 
at  the  bottom,  allowing  the 
fruit  to  be  emptied  into  the 
lug-boxes  gently  and  without 
bruising. 

Many  different  types  of  lad- 
ders are  used,  the  prevailing  one 
having  a  third  leg  on  hinges 
which  is  let  down  through  the 
branches  and  rests  on  the 
ground  near  the  base  of  the 
tree.  Simple  ladders  which  rest 
against  the  branches  are  not 
recommended,  as  they  cause  too 
much  injury  to  the  fine  fruiting  brush.  Sometimes  it 
is  necessary  to  climb  up  into  the  crotches  of  the  trees 
to  reach  inside  fruit.  This  should  be  avoided  as  much  as 
possible,  as  the  heavy  shoes  of  the  pickers  scar  the  bark 
and  may  carry  the  germs  of  gum-disease,  especially  when 
the  surface  of  the  soil  is  wet. 


Fig.    97.  —  Dashboard     pick 
ing  bag. 


Picking  and  Packing  Oranges 


281 


Some  growers  designate  one  man  in  each  picking  gang 
to  do  what  cHmbing  is  necessary  and  require  that  man  to 
wear  a  grain  sack  tied  about  each  shoe  in  order  to  avoid 
bruising  the  bark  of  the  trees.  In  moving  Ladders  about 
great  care  should  be  taken  to  avoid  injury  to  the  fine 
fruiting  brush  which  must  be  depended  upon  to  bear 
succeeding  crops. 

The  fruit  after  being  picked  is 
transferred  to  the  hig-boxes  which 
are  never  filled  quite  full.  These 
lug-boxes  are  then  stacked  one  on 
top  of  the  other  on  the  shady  side 
of  the  trees  to  await  the  spring  wagon 
which  conveys  them  to  the  packing- 
house. 

It  is  often  customary  to  pick  the 
fruit  from  the  lower  branches  first, 
leaving  the  high  fruit  till  later  in 
the  season.  There  are  two  reasons 
for  this.  One  is  that  frost  is  often 
more  severe  near  the  ground,  and 
low-hanging  fruit  picked  early  is  out 
of  the  way  of  frosts.  Secondly,  the 
brown  rot  fungus  grows  in  the  soil, 
and  during  wet  spells  comes  to  the  surface  and  fruits.  The 
spores  are  splashed  by  the  rains  up  on  the  low-hanging 
fruit,  causing  decay.  It  should  be  pointed  out  that  this 
fungus  is  different  in  its  action  from  most  other  fungi  in  not 
needing  an  abrasion  for  entrance  into  a  sound  fruit.  The 
spores  are  motile,  and  when  there  is  a  film  of  rainwater 
on  the  surface  of  the  fruit  these  spores  are  capable  of 


Fig.     98.  —  Covina 
picking  bag. 


282 


Citrus  Fruits 


swimming  into  the  stomates  or  natural  breathing  pores 
and  causing  decay.  This  finigus  causes  most  trouble  near 
the  coast,  and  low-hanging  fruit  need  not  be  picked  early 
in  the  interior  valleys  on  this  account. 

Occasionally  oranges  are  picked  according  to  size  on 
orders  from  the  packing-house  which  desires  a  preponder- 
ance of  large  or  small  sizes  as  the  case  may  be  to  meet 
the  requirements  of  some  certain  market. 
Sometimes,  also,  in  the  case  of  a  very 
heavy  crop,  it  is  advisable  to  thin  the 
fruit  on  the  trees  rather  than  to  pick  it 
clean  the  first  time.  This  is  done  to  ease 
the  strain  on  the  branches  and  permit  the 
props  to  be  removed. 

It  has  been  customary  to  pay  pickers  by 
the  day  rather  than  by  the  box.  Piece 
work  encourages  careless  handling  and  an 
increase  in  the  amount  of  decay. 

The  process  known  as  "  sweating, "  by 
which  the  color  of  oranges  is  changed  from 
green  to  yellow,  is  illegitimate  when  em- 
ployed for  the  purpose  of  deceiving  the 
consumer  as  to  the  quality  of  the  orange.  Immature  fruit 
may  not  be  colored  in  the  sweat-room  and  sold  before  it 
is  fit  to  eat.  There  are  cases,  however,  in  which  sweating 
is  perfectly  legitimate.  Mature  Valencia  oranges  often 
develop  a  green  color  during  their  second  summer  on  the 
trees,  and  a  light  sweating  to  restore  the  former  yellow 
color  deceives  no  one,  and  is  commonly  practiced.  -In 
some  locations  also  the  fruit  becomes  sweet  before  it  is 
fully  yellow.     The  coloring  of  such  fruit  may  be  finished 


Picking  and  Packing  Oranges 


283 


in  the  sweat-room,  providing  always  that  such  treatment 
is  restricted  to  fruit  which  is  otherwise  mature  and  in 
good  condition  to  eat. 

Very  good  prices  are  usually  recei\ed  for  the  earliest 


Fig.  100.  —  The  Wis.s  clipper  now  Li;iiig  .^uperoeJed  by  the  Tuttle  shown 
in  Pig.  96. 

Navel  oranges  sent  to  Eastern  markets.  This  has  resulted 
in  recent  years  in  considerable  competition  for  the  early 
markets  and  the  shipment  of  much  fruit  which  is  im- 
mature and  not  satisfactory.  Sometimes  oranges  are 
picked  as  early  as  the  first  week  in  October,  while  still 
perfectly  green  in  color,  colored  by 
sweating  and  hurried  to  market. 
While  some  of  this  fruit  brings  high 
prices  the  result  is  disastrous  for  the 
much  better  fruit  which  follows.  This 
unwise  shipment  of  immature  fruit  re- 
sulted in  so  much  loss  and  dissatisfac- 
tion among  the  growers  of  both  Cali- 
fornia and  Florida  that  the  legislature 
of  the  state  of  Florida  on  June  13, 
1913,  passed  an  immature  fruit  law 
been  enforced  with  some  good  results, 
the  shipment  of  green  fruit  between  September  1  and 
November    5    of  each  year   which    shows    by    test    to 


Fig.  101.  — Metal  at- 
tachment for  prop- 
ping limbs. 

which    has    since 
This  law  forbids 


284 


Citrus  Fruits 


contain  in  the  juice  more  than  1.3  per  cent  of  acid. 
A  simple  and  cheap  method  of  making  the  acid  test 
was  worked  out  by  the  state  chemist  and  placed  at 
the  disposal  of  all  growers.  Between  September  1  and 
November  5  inspectors  traveled  through  the  state  taking 
samples  and  making  tests  at  the  various  packing-houses. 


Fig.  102.  —  Worm  brushes  used  for  polishing  oranges. 

The  simple  field  test  was  used,  but  in  the  case  of  dispute 
the  remainder  of  the  sample  was  sent  to  the  state  chem- 
ist for  more  accurate  analj^sis. 

Some  time  before  the  Florida  law  was  passed  the  Federal 
Board  of  Food  and  Drugs  Inspection  took  notice  of  the 
artificial  coloring  of  immature  oranges  by  sweating,  and 
made  the  following  ruling  : 


Picking  and  Packing  Oranges 


FOOD   INSPECTION   DECISION   133 


285 


The  Coloring  of  Green  Citrus  Fruits 

The  attention  of  the  Board  of  Food  and  Drug  Inspection 
has  been  directed  to  the  shipment  in  interstate  commerce 
of  green,  immature  citrus  fruit,  particuhirly  oranges,  which 
have  been  artificially  colored  by  holding  in  a  warm,  moist 
atmosphere  for  a  short  period  of  time  after  removal  from  the 
tree.  Evitlence  is 
adduced  showing 
that  such  oranges 
do  not  change  in 
sugar  or  acid  con- 
tent after  removal 
from  the  tree. 
Evidence  further 
shows  that  the 
same  oranges  re- 
maining on  the 
tree  increase 
markedly  in  sugar 
content  and  de- 
crease in  acid  content.  Further,  there  is  evidence  to  show 
that  the  consumption  of  such  immature  oranges,  especially 
by  children,  is  apt  to  be  attended  by  serious  disturbances  of 
the  digestive  system. 

Under  the  Food  and  Drugs  Act  of  June  30,  1906,  an  article 
of  food  is  adulterated  "if  it  be  mixed,  colored,  powdered, 
coated,  or  stained  in  a  manner  whereby  damage  or  inferi- 
ority is  concealed."  It  is  the  opinion  of  the  Board  that 
oranges  treated  as  mentioned  above  are  colored  in  a  manner 
whereby  inferiority  is  concealed  and  are,  therefore,  adulter- 
ated. 


Fig.  103.  —  Rope  feed  hopper. 


286 


Citrus  Fruits 


The  Board  recognizes  the  fact  that  certain  varieties  of 
oranges  attain  maturity  as  to  size,  sweetness,  and  acidity 
before  the  color  changes  from  green  to  yellow,  and  this 
decision  is  not  intended  to  interfere  with  the  marketing  of 
such  oranges. 

H.  W.  Wiley, 
f.  l.  dunlap, 
Geo.  p.  McCabe, 
Board  of  Food  and  Drug  Inspection. 
Approved : 

James  Wilson, 

Secretary  of  Agriculture, 
Washington,  D.  C,  March  28,  1911. 


The  enforcement  of  this  ruling  has  done  a  certain 
amount  of  good,  but  it  has  not  entirely  put  a  stop  to  the 
irresponsible  shipment  of  worthless  fruit,  for  the  reason 


Picking  and  Packing  Oranges 


287 


that  it  applies  only  to  fruit  which  has  been  artificially 
colored.^ 


I  w  1    4  SB  H 


Fig.  105.  —  Box  press  and  nailing  maohino. 

'  Where  there  is  li\ang  vegetable  tissue  there  is  respiration, 
and  carbon  dioxide  and  water  are  given  off.  That  the  respiration 
of  stored  oranges  takes  place  at  the  expense  of  sugar  and  acid 
and  results  in  the  gradual  reduction  in  the  amounts  of  these 
substances  has  been  shown  to  be  true  by  investigations  carried 
on  in  the  U.  S.  D.  A.  Bureau  of  Chemistry  in  1905. 

"  During  the  storage  (of  Navel  oranges)  there  was  a  slight  loss 
in  acid  and  in  sugar.     This  is  confirmatory  of  similar  results 


288 


Citrus  Fruits 


Navel  oranges  color  earlier  and  become  sweet  earlier 
in  central  than  in  sonthern  or  northern  California.  The 
apparent  advantage  in  sweetness  of 
early  oranges  from  southern  San 
Joaquin  Valley  is  not  due  so  much 
to  an  early  increase  in  total  sugars  as 
it  is  to  an  early  increase  in  the  ratio 
between  sugar  and  acid.  Colby  ^  has 
shown  that  it  is  the  early  decrease 
in  acid,  together  with  the  early  color- 
ing, which  enables  the  growers  in  the 
San  Joaquin  \'alley  to  market  their 
oranges  early. 

Recently  C.  L.  Alsberg,  chief  of 
the  Bureau  of  Chemistry,  U.  S.  D. 
A.,  suggested  that  as  a  result  of  in- 
vestigations carried  on,  the  northern 
district  oranges  may  be  considered  to  be  immature  when  the 
juice  does  not  contain  soluble  solids  equal  to  or  in  excess  of 
eight  parts  to  each  part  of  acid  present,  acid  to  be  calcu- 


FiG.  106.— Citrus  fruit 
truck. 


with  apples  and  peaches,  and  is  probably  due  to  the  decomposi- 
tion of  acid  and  sugar  in  the  respiration  of  the  fruit."  .  .  .  "The 
loss  of  acid  and  sugar  noted  above  is  to  be  explained,  as  in  the 
case  of  apples,  by  the  consumption  of  these  substances  as  a 
result  of  respiration  of  the  fruit."  —  W.  D.  Bigelow  and  H.  C. 
Gore,  "Ripening  of  Oranges."  Read  before  A.  A.  A.  S.  in 
New  Orleans,  1905.  Contribution  from  the  Bureau  of  Chemistry, 
U.  S.  Dept.  Agr.  —  Published  in  Journal  American  Chemical 
Society,  Vol.  29,  No.  5,  1907. 

^  G.  E.  Colby,  "Comparative  Examination  of  Shipping  Navel 
Oranges  from  Northern,  Middle,  and  Southern  California," 
California  Agr.  Exp.  Sta.  RpL,  1898-1901,  Part  II,  pp.  243- 
251. 


Picking  and  Packing  Oranges 


289 


lated  as  citric  without  water  of  crystallization.  It  was 
decided  to  base  this  figure  upon  the  acid  solids  ratio  in 
preference  to  the  acid  sugar  ratio  for  the  reason  that  the 
growers  and  packing-house  foremen  would  be  able  to 
make  the  necessary  analyses,  which  would  be  impossible 
in  the  case  of  sugars. 

Since  this  valuable  suggestion  was  made  growers  and 
shippers  throughout  the  early  districts  have  applied  the 
test  quite  generally  and  are 
cooperating  in  limiting  ship- 
ments to  fruit  which  shows 
the  8-1  ratio.  The  effect  of 
this  has  been  very  beneficial 
as  shown  by  market  reports. 

Shippers  of  oranges  will  do 
well    not    to    pick    the    fruit 
until  it  is  in  condition  to  be 
enjoyed  on  the  tables  of  the 
growers   themselves.     If    the 
orange   industry   in   northern         Fig- 107.  -  Packing  stand. 
California  is  to  grow  to  great  proportions,  it  must  do  so 
on  a  basis  of  satisfactory  fruit.     Every  orange  sent  to 
market  should  stimulate  in  the  buyer  a  desire  for  more 
of  the  same  kind. 

The  siceat-rooni.  —  The  sweat-room  is  an  air-tight,  fire- 
proof chamber  usually  built  separate  from  the  main  part 
of  the  packing-house.  Beneath  a  false  floor  are  placed 
kerosene  burning  stoves  of  a  type  which  does  not  give 
complete  combustion.  The  hot  gases  and  water  vapor 
pass  up  through  the  floor  and  envelop  the  fruit.  The 
temperature  is  controlled  by  ventilators  in  the  roof  and  is 
u 


290  Citrus  Fruits 

kept  for  oranges  at  100°  F.  for  from  three  to  five  days,  or 

until  the  oranges  are  properly  colored.     During  this  time 

the  air  in  the  sweat-room  should  be  kept  quite  moist  to 

prevent  wilting  and    shri\'eling  of   the  fruit.     This  will 

require  close  watching,  as  the  air  will  dry  out  with  some 

lots  of  fruit  and  tend  to  remain  saturated 

B  with  other  lots.     Pans  of  water  may  be 

M  set  on  the  stoves,  and  occasionally  it  is 

«  necessary  to  wet   down  the  fruit   and 

M  the  sides  and  floor  of  the  room  in  addi- 

■  tion.     The  fruit  should  be  graded  ac- 

■  cording  to  shade  of  color,  the  lightest 

■  being  placed  next  the  door,  so  that  it 
M  may  be  removed  earlier  than  the  rest  if 

■  desirable.      The    air  should  be  a  little 

■  less  than  saturated  with  moisture. 

^     I  When  the  coloring  of  citrus  fruit  is 

^^11^^         forced  too  rapidly  the  buttons  (stems) 

^^P^^B^^     shrink  away  and  drop  off.     This  is  very 

^^^^^Wj     undesirable,  as  fruit  without  buttons  is 

"     not  supposed  to  keep  as  well  and  is  dis- 

FiG.   108.  —  Box     counted  in  the  markets.     When  used  to 

?ze^^^^      ^"^'^     excess  the  same  gases  which  color  the 

fruit  throw  the  buttons. 
In  very  few  places  in  California  does  the  fruit  come  to 
the  packing-house  sufficiently  clean  to  pack.  In  interior 
valleys  it  is  covered  with  a  layer  of  dust,  and  near  the 
coast  it  is  apt  to  show  scale  insects  or  the  black  smut 
(Meliola  camellia)  which  is  a  fungous  growth  on  the  honey 
dew  or  excretions  of  scale  insects.  If  fruit  is  simply  dusty, 
it  is  run  through  a  series  of  rapidly  revolving  dry  roller 


Picking  and  Packing  Oranges  291 

brushes.  In  some  cases  it  may  have  a  spray  of  water 
directed  upon  it  while  in  the  brushes  or  it  may  pass  in 
water  between  two  series  of  submerged  brushes.  In  the 
latter  case  a  tank  is  necessary,  and  it  is  good  policy  to 
disinfect  the  wash  water  against  brown  rot  infection. 
Wash  water  for  oranges  is  usually  disinfected  by  the 


Fig.  109.  — Car  squeeze.     Large  size. 

addition  of  one  pound  of  permanganate  of  potash  to  1000 
gallons  of  w^ater  in  the  morning,  and  at  noon  2  pound  is 
added  to  the  same  water.  The  water  in  the  tank  is 
changed  each  day. 

After  being  washed  the  fruit  is  conveyed  by  belts  to 
drying  racks  in  the  open  or  under  cover,  or  is  run  through 
an  air-blast  dryer. 

The  fruit  next  passes  on  belts  or  roller  ways  before  the 


292  Citrm  Fruits 

graders  who,  considering  color,  shape,  smoothness,  and 
blemishes,  sort  the  salable  fruit  into  three  grades,  stand- 
ard, choice,  and  fancy,  placing  each  grade  on  a  separate 
belt  which  conveys  it  to  its  respective  automatic  weighing 
machine  where  the  proper  proportion  of  each  grade  is 
credited  to  the  grower.  After  the  oranges  pass  the  weigh- 
ing machines  their  identity  is  merged  in  the  general  pool 
of  the  house. 

The  fruit  next  passes  through  the  sizing  machines,  of 
which  there  are  a  great  many  different  types,  and  each 
size  is  delivered  to  a  separate  bin.  The  bins  are  carefully 
padded  on  bottom  and  sides  with  cotton  cloth,  and 
have  movable  sides  which  provide  for  adjustment  of 
capacity. 

Box  shooks  are  usually  bought  in  Oregon  or  northern 
California,  and  the  boxes  are  made  in  the  basement  of 
the  packing-house.  They  are  made  either  by  hand  or 
by  an  automatic  box  making  machine.  A  standard  box 
of  California  oranges  is  12  by  12  by  26  inches  outside 
measurement.  It  is  divided  in  the  middle  by  a  partition. 
For  purposes  of  computing  freight  charges  it  is  estimated 
to  weigh  when  packed  72  pounds. 

On  the  end  of  each  box  is  pasted  a  paper  label,  usually 
a  five-color  lithograph,  showing  some  picture  appropriate 
to  the  brand.  Each  packing-house  or  association  has  a 
series  of  brands  copyrighted  for  its  own  use.  In  addition 
to  this  the  finest  quality  fruit  sold  through  the  Cali- 
fornia Fruit  Growers'  Exchange  bears  the  additional 
"Sunkist"  label  of  the  Exchange.  The  variety  and  size 
of  the  fruit  and  the  packer's  number  is  stenciled  on  the 
end  of  each  box.     Boxes  which  are  liable  to  be  sold  in 


Picking  and  Packing  Oranges  293 

New  York  State  are  now  stenciled  with  the  exact  dimen- 
sions and  cubical  contents  of  the  box. 

Box  shooks  are  made  of  Pacific  Coast  pine  exclusively. 
The  standard  8  slat  orange  box  requires  SiVff  feet  of 
lumber  and  costs  about  ISl  cents  delivered.  The  standard 
lemon  box  contains  j  foot  more  lumber  and  costs  on  an 
average  15|  cents.  The  cheaper  grades  of  tissue  wrap- 
pers come  from  mills  in  Oregon  and  California,  while  the 
fine  grades  come  from  Hamburg,  N.  J.  The  paper  is 
printed  in  Los  Angeles  from  wide  rolls  on  cylinder  presses. 
The  cost  printed  and  delivered  to  the  packing-houses  for 
the  10X10,  an  average  size,  is  about  $17.50  a  hundred 
thousand.  A  pound  contains  about  414  sheets.  Box 
labels  are  procured  from  lithograph  houses  and  are  usually 
done  in  five  colors.  They  cost  about  $3.00  per  thousand. 
Special  cement  coated  nails  are  used  which  cost  in  large 
lots  about  three  cents  a  pound.  INIetal  box  strapping 
comes  from  New  Jersey  chiefly  in  6500  foot  reels  and  costs 
about  $1.46  a  thousand  feet.  From  18  to  24  inches  of 
strapping  is  used  on  each  box.  Most  of  the  larger  packing- 
houses use  beveling  machines  for  the  ends  and  partitions 
and  box  making  machines  for  putting  the  boxes  together. 

Both  women  and  men  are  employed  as  packers,  women 
being  most  largely  used.  The  empty  box  is  placed  on  a 
packing  stand  which  rests  on  rollers  and  has  a  revolving 
top.  The  hod  holding  tissue  wrapping  paper  is  placed 
over  one  end  of  the  box.  The  packers  stand  beside  the 
sizing  bins,  and  wrapping  each  fruit  in  printed  absorbent 
tissue  paper,  place  it  in  the  box  with  great  dexterity  and 
skill,  averaging  about  sixty  boxes  a  day.  The  fruit  is 
placed  in  the  box  in  its  respective  order  of  arrangement 


294 


Citrus  Fruits 


Picking  and  Packing  Oranges  295 

according  to  the  size.  Each  size  of  fruit  has  its  own  order 
of  arrangement  and  the  size  is  designated  in  the  house 
and  on  the  market  not  by  the  diameter  of  each  orange, 
but  by  the  number  required  to  fill  a  box.' 

Oranges 

Size  Average  Diameter  in  Inches 

64 3  = 

80 3i 

96 3f 

112 S\ 

126 3i 

150 3 

176 2| 

200 2| 

216 2f 

250 21 

288 2f 

324 2\ 

360 2i 

A  very  high  pack  is  customary,  and  after  the  covers  are 
forced  on  and  nailed  the  boxes  are  usually  delivered  by 
automatic  carrier  to  the  car  or  precooling  room.  One 
hundred  field  boxes  will  usually  pack  out  about  sixty 
packed  boxes.  The  cars  vary  in  capacity,  depending  on 
whether  they  are  provided  with  collapsible  ice  bunkers. 
The  standard  car  of  oranges  contains  3S-i  boxes  loaded 
two  tiers  on  end  and  six  rows  wide  and  including  sizes 
96,  112,  and  250,  and  not  over  20  per  cent  of  the  126 
size.  The  remainder  of  the  car  may  be  divided  among 
the  150,  176,  and  216  sizes.  Cars  other  than  standard  are 
discounted  from  25  to  50  cents  a  box  on  the  market 
according  to  the  number  of  off  sizes  they  contain. 

^  For  further  rules  governing  packing,  see  Chapter  VIII. 


296 


Citrii.s  Fruits 


The  boxes  are  set  with  two  inch  air  spaees  running 
lengthways  the  ear.  Each  tier  of  boxes  is  braced  in 
position  by  a  narrow  strip  running  across  the  car  and 


Fig.  111.  — Oraiij^c  pttekt-rs  at  work. 


nailed  to  each  box.  As  the  tiers  are  set  the  slack  through- 
out the  car  is  taken  up  by  a  device  known  as  a  "  car 
squeeze."     A  copy  of  the  manifest  card  showing  the  num- 


Picking  and  Packing  Oranges  297 

ber  of  different  sizes  and  their  location  in  the  car  is  tacked 
on  the  inside  wall  near  the  door. 

The  freight  is  figured  on  an  estimated  weight  of  72  lb. 
to  the  box,  and  is  $1.15  a  hundred  pounds  to  points  on 
the  Missouri  River  and  eastward.  Icing  charges  are 
extra. 

Precooling 

The  term  "  precooling  "  properly  applied  relates  to  the 
reduction  in  the  temperature  of  any  given  lot  of  fruit  before 
it  is  dispatched  on  its  journey  to  market,  in  contradistinc- 
tion to  the  usual  method  of  reducing  the  temperature 
gradually  in  transit.  It  has  been  found  by  experiment 
that  when  warm  fruit  is  loaded  into  cars  with  ice  and 
started  on  its  journey  across  the  desert  that  before  the 
fruit  in  the  center  of  the  boxes  is  thoroughly  chilled, 
decay  has  set  in.  This  decay  is  checked,  but  on  unloading 
the  fruit  in  the  warm,  humid  climate  of  the  East  such 
decay  spreads  rapidly.  With  precooled  fruit  the  decay 
has  not  been  allowed  to  become  so  much  advanced,  and 
ears  do  not  require  such  frequent  re-icing.  Precooling  will 
not  take  the  place  of  careful  handling. 

Inasmuch  as  citrus  fruits,  when  carefully  handled,  keep 
excellently  for  long  periods  at  ordinary  temperatures, 
precooling  is  not  as  valuable  with  them  as  it  is  with  other 
more  tender  and  quickly  perishable  fruits.  Several 
packing  associations  have  adopted  the  practice  of  sending 
their  fruit  to  market  "  under  ventilation  "  or  without  ice, 
but  it  requires  great  care  in  picking,  handling,  and  packing 
to  be  able  to  do  this  successfully. 

The  large  precooling  plants  which  chill  a  whole  train 


298  Citrus  Fruits 

load  of  thirty  cars  simultaneously  by  driving  or  circulating 
a  blast  of  cold  air  through  the  cars,  are  owned  by  the  rail- 
road companies  who  desire  that  precooling  be  considered 
a  function  of  the  transportation  companies.  Some 
packing  associations  which  had  built  small  precooling 
plants  of  their  own  objected  to  the  above  point  of  view  and 
fought  their  case  in  the  courts  for  several  years,  finally 
winning  their  point  before  the  U.  S.  Supreme  Court  in 
January,  1914.  The  Court  ruled  that  S7.50,  for  each  re- 
icing,  the  rate  set  by  the  Interstate  Commerce  Commission, 
was  reasonable  and  applicable  to  precooled  shipments. 
The  rate  previously  charged  by  the  railroads  for  icing  cars 
was  $62.50  for  the  trip,  regardless  of  whether  much  or  little 
ice  was  needed.  Inasmuch  as  precooled  cars  only  require  a 
comparatively  small  amount  of  ice  en  route,  the  saving  to 
the  growers  by  this  decision  amounts  to  about  $30  a  car. 

About  55  per  cent  of  the  oranges  shipped  East  go  forward 
under  ice.  In  very  cold  weather  and  especially  for  cars 
sent  to  the  extreme  North,  it  is  advisable,  before  loading, 
to  paper  the  inside  of  the  car  with  several  thicknesses  of 
heavy  building  paper  to  prevent  the  fruit  from  being 
frozen  en  route. 

The  average  haul  for  cars  shipped  east  of  the  JNIississippi 
River  is  2585  miles  and  the  average  time  between  San 
Bernardino,  where  the  Santa  Fe  overland  citrus  trains 
are  made  up,  or  Colton,  where  the  Southern  Pacific  trains 
are  made  up,  and  New  York  is  about  fourteen  days. 

After  many  years  of  effort  the  citrus  growers  have  gained 
from  the  railroads  the  right  of  diversion,  which  means 
that  a  car  of  oranges  may  be  billed  to  Chicago,  for  in- 
stance, and  when  it  arrives  should  the  Chicago  market 


Picking  and  Packing  Oranges 


299 


be  unfavorable  it  may  be  diverted  to  Cleveland  or  Buffalo 
or  Boston  or  to  any  other  place  toward  the  East  and 
within  that  traffic  zone  without  additional  char<je. 

There  are  two  concerns  in  southern    ("alifornia   which 


Pine  Cone 

^^^       BBAHD 

f^;  WASHINOION  NAVELS 

m 


Grown  ■•  packld  by 

Highland 
Orange 

ASSOCIATION 

41IGHLAND, 

SAN  BERNARDINO  CO. 


Fig.  112.  — a  ty 


make  a  specialty  of  designing  and  constructing  packing- 
houses and  manufacturing  special  equipment.  ]\Iost 
orange  houses  consist  of  a  basement,  where  shook  and 
other  supplies  are  stored  and  where  boxes  are  made,  and 
a  packing  floor  where  fruit  is  handled  from  delivery  wagon 


300 


Citrus  Fruits 


>^^^■^^^^^'^■^'.^^■^'.'-■-■-^'^T- 


^1     ^ 


Picking  and  Parking  Oranges  301 

to  the  car.  The  fire  hazard  is  high  and  losses  are  rather 
frequent.  Most  of  the  houses  belong  to  a  local  mutual 
insurance  association  which  prorates  and  assures  the 
losses  as  they  occur. 

There  are  at  present  about  200  packing-houses  in  active 
operation  in  ("alifornia,  besides  a  large  number  of  sheds 
and  old  houses  which  operate  only  at  infrequent  intervals. 
The  capacity  of  the  houses  varies  from  one  to  twenty  cars 
a  day. 

The  associations  which  are  affiliated  with  the  Exchange 
enjoy  the  privilege  of  buying  ranch  and  packing-house 
supplies  through  the  Fruit  Growers'  Supply  Co.  This 
is  a  non-profit  cooperative  organization  through  which 
the  growers  pool  their  orders  at  low  cost.  The  Sup- 
ply Company  has  an  authorized  capital  of  one  million 
dollars  and  in  1914  did  a  business  of  $3,319,062.04  at  an 
operating  expense  to  the  members  of  f  of  one  cent  on 
each  dollar  of  business  transacted. 


CHAPTER   XVI 


PICKING   AXD    PACKING   LEMONS 


The  picking  and  packing  of  lemons  differs  radically 
from  that  of  oranges  as  described  in  the  previous  chapter. 

Lemons  are  usu- 
ally picked  from 
ten  to  twelve 
times  a  year,  the 
heaviest  pickings 
coming  in  ^Nlarch 
and  April  and 
the  lightest  in 
August  and  Sep- 
tember. It  is  a 
peculiar  and  un- 
fortunate fact 
that  the  heavy 
pickings  come  at 
a  time  of  year 
when  there  is  lit- 
tle demand  for 
lemons  and  the 
Hghtest  pickings 
come  during  the 
picnic  and 
lemonade  season, 
302 


Picking  and  Packing  Lemons 


303 


when  the  demand  is  greatest.  For  this  reason  the  proper 
storage  of  spring  lemons  becomes  one  of  the  important 
functions  of  the  lemon  packing-house. 

The  following  typical  example  of  an  actual  yield  of  a  9j 
acre  mature  lemon  orchard  of  mixed  Eurekas  and  Lisbons 
growhig  near  Covina,  Los  Angeles  County,  gives  a  good 
comparison  of  the  various  pickings : 

Record  of  Lemon  Pickings.  Season  1910-11 
Orchard  of  Mr.  N.  D.  Mussey 


Pool 

Date 

Lug-boxes 

Pounds 

1 

Sept.  19 

76 

3,698 

2 

Oct.  19 

60 

2,880 

3 

Nov.  17 

289 

13,852 

4 

Jan.  3 

520 

24,470 

5 

Feb.  1 

832 

39,415 

6 

Alfir.  18 

1,122 

50,906 

7 

May  3 

1,120 

51,350 

8 

May  30 

196 

9,268 

9 

July  21 

298 

14,224 

10 

Aug.  30 

52 

2,506 

Total 

4,565 

212,569 

The  method  of  picking  lemons  from  the  trees  is  much  the 
same  as  with  oranges  except  that  the  use  of  the  ring  and 
consequent  searching  about  in  the  foliage  among  fruit  of 
all  sizes  makes  picking  slower  and  more  expensive.  Es- 
pecial care  should  be  used  to  prevent  dead  twigs  and  other 
trash  from  falling  into  the  picking  sacks  as  the  weight  of 


304 


Citrufi  Fndis 


the  lemons  against  such  objects  in  handling  will  cause 
scratches  in  the  skin.  In  some  sections  special  picking 
sacks  with  closed  tops  are  used  to  ])revent  this.  In  this 
type  of  sack  the  fruit  is  introduced  at  the  side  near  the 
top. 

For  hauling  to  the  packing-house  the  growers  generally 
use   a    factory-made    wooden    wagon    with    steel    skeins 


Fig.  115.  —  Two-story  lemon  packing  house,  Glendora,  California. 


on  which  they  place  a  wide  flat  rack  usually  about  8  feet 
wide  and  14  feet  long.  The  racks  are  made  locally  and 
are  set  on  the  gears  over  bolster  springs.  It  is  not  un- 
common to  see  a  string  of  three  or  more  of  these  wagons 
hooked  together  and  being  drawn  by  the  gas  tractor 
which  is  used  for  cultivating  the  orchards. 

Lemons  differ  from  oranges  also  in  being  valued  for 
their  acid  rather  than  for  their  sugar  content.     A  green 


Picking  and  Packing  Lemons  305 

lemon  therefore  is  better  than  a  yellow  "  tree  ripe  "  one 
provided  it  is  fully  sized  and  mature.  For  these  reasons 
lemons  are  picked  altogether  according  to  size  rather  than 
color.  The  pickers  carry  wire  rings  which  are  slipj)ed  over 
each  lemon,  and  every  fruit  which  fails  to  pass  through  the 
ring  is  picked.  In  summer  aring2|  inches  in  diameter, 
inside  measurement,  is  used ;  while  in  winter  and  spring 
a  ring  one-sixteenth  of  an  inch  larger  is  used,  inasmuch 
as  the  fruit  will  be  held  longer  and  will  undergo  greater 
shrinkage. 

On  account  of  the  demands  of  the  markets  mentioned 
above,  there  is  a  tendency  to  pick  often  in  summer,  care- 
fully searching  for  every  lemon  which  may  be  up  to  size. 
This  fruit  is  quickly  colored  in  the  sweat-room  and  hurried 
to  market  while  prices  are  high. 

SWEATING    AUTUMN    LEMONS 

The  sweathig  of  lemons  is  for  the  purpose  of  quickly 
changing  the  green  color  to  a  whitish  yellow.  While 
the  practice  of  sweating  oranges  is  sometimes  abused, 
lemon  sweating  is  always  legitimate  as  it  in  no  way  de- 
ceives the  buyer.  In  fact  the  mature  but  green  lemon 
properly  colored  in  the  sweat-room  antl  hurried  to  market 
is  usually  sourer,  and  therefore  better,  than  the  lemon 
which  lias  been  kept  in  storage  for  several  months  and 
has  consumed  a  small  portion  of  the  acid  in  the  process 
of  respiration. 

For  best  results,  lemons  should  be  fired  intermittently. 
The  air  of  the  sweat-room  should  be  kept  saturated  with 
moisture,  and  beads  of  water  should  be  in  evidence  on 

X 


306  Citru.s-  Fruits 

the  ceiling  at  all  times.  If  the  air  is  allowed  to  become 
dry,  the  lemons  will  quickly  shrivel.  The  temperature 
should  be  kept  at  90°  F.  or  ten  degrees  lower  than  for 
oranges.  So  far  it  has  been  impossible  to  fully  color 
green  lemons  in  five  days  and  retain  the  buttons,  as  the 
same  quality  of  the  gas  mixture  which  changes  the  color 
causes  the  buttons  to  drop  off.  Inasmuch  as  sweated  lem- 
ons are  sold  and  consumed  quickly,  the  loss  of  the  buttons 
is  not  as  serious  a  matter  as  would  otherwise  be  the  case. 


STORAGE    OF   WINTER    LEMONS 

In  the  late  winter  and  spring  when  it  becomes  advisable 
to  hold  the  fruit  for  summer  markets,  the  problem  of  the 
lemon  packer  is  very  different  from  that  of  early  fall. 
Instead  of  sweating  the  fruit  and  thus  accelerating  the  life 
processes  as  much  as  possible,  he  now  wishes  to  retard 
to  the  greatest  possible  degree  these  same  life  processes. 
The  fruit  is  therefore  picked  with  very  great  care  in  order 
to  prevent  abrasions.  On  arriving  at  the  packing-house 
the  lemons  are  carefully  washed  in  a  brush  washer.  For 
disinfection  against  brown  rot,  one  pound  of  bluestone  is 
added  to  each  1000  gallons  of  wash  water  in  the  morning 
and  one-half  pound  added  to  the  same  water  at  noon,  the 
water  being  changed  each  morning.  To  prevent  the 
bluestone  from  corroding  metal  tanks  it  is  well  to  apply 
a  thick  coat  of  asphaltum  paint  to  the  inside  of  the  tank. 

The  lemons  are  now  separated  into  three  grades  accord- 
ing to  color  alone,  known  as  green,  silver,  and  tree-ripe ; 
the  silver  being  those  fruits  which  are  just  beginning  to 
lose  the  deep  green  color.     Each  of  these  grades  is  placed 


Picking  and  Parking  Lemons 


307 


loosely  ill  packing  boxes  and  stacked  uj),  a  car  in  each 
stack,  on  the  storage  floor.  Lemons  are  often  kept  in  this 
way  six  or  even 
eight  months, 
but  the  fruit 
picked  after  April 
1  is  much  shorter 
lived  than  that 
picked  earlier. 
Lemons  picked 
green  will  keep 
much  longer  than 
those  allowed  to 
turn  yellow  on 
the  tree.  These 
tree-ripes  are 
kept  separate  and 
shipped  first. 
Lemons  will  also 
keep  much  better 
near  the  coast 
than  in  the  in- 
terior valleys, 
where  much  more 
expensive  storage 
houses  must  be 
provided  in  order 
to  control  the 
humidity.       The 

great  problem  is  to  give  plenty  of  ventilation  in  damp 
weather  in  order  to   prevent  decay  and   to  reduce  the 


Fig. 11 


1  washing  machine  and  sort- 
ing table. 


308  Citrm  Fruits 

ventilation,  or  withhold  it  entirely  in  warm  dry  weather 
to  prevent  the  fruit  from  losing  moisture  and  shrivel- 
ing. The  relative  humidity  of  the  air  in  the  storage 
house  should  be  held  as  near  80  per  cent  as  possible,  but 
this  is  very  difficult  to  accomplish  in  interior  valleys, 
where  the  humidity  of  the  air  varies  from  90  per  cent  to  as 
low  as  10  per  cent.  In  order  to  control  the  temperature 
and  humidity  each  carload  stack  of  lemons  is  inclosed  in 
a  heavy  duck  tent.  These  tents  are  usually  made  of  8  oz. 
special  army  duck,  and  are  10'  wide,  10'  high,  and  20'  long. 
This  size  includes  one  carload  of  lemons.  This  tent  is 
open  at  the  bottom,  and  is  open  at  the  four  corners,  which 
are  laced  so  that  any  part  of  the  fruit  may  have  ventila- 
tion, without  interfering  with  fruit  that  it  is  not  necessary 
to  ventilate.  These  tents  are  also  built  in  other  sizes, 
which  is  sometimes  necessary  to  fit  the  space  in  a  packing- 
house, but  this  is  the  size  that  is  most  generally  used. 
The  tent  is  hung  from  the  ceiling  on  a  frame,  there  being 
eyelets  in  the  top  to  fasten  to  frame.  In  some  of  the 
packing-houses  in  interior  districts  the  tents  have  been 
abandoned  and  the  fruit  is  stored  in  large  basements, 
usually  built  of  concrete,  with  outside  shutters  which 
provide  for  ventilation. 

Unless  the  lemons  have  been  very  carefully  handled 
from  the  orchard  to  the  packing-house,  a  great  deal  of 
decay  is  almost  sure  to  develop  in  storage.  Lemons  are 
always  handled  more  carefully  than  oranges  and  the  brush 
washer  is  about  the  only  piece  of  machinery  they  are 
allowed  to  pass  through.  On  account  of  the  absence  of 
machinery,  a  lemon  packing  house  presents  a  very  different 
aspect  from  an  orange  packing  house. 


Picking  and  Packing  Lemons 


309 


When  the  fruit  is  taken  from  storage  it  is  graded  by 
hand  into  fancy,  choice,  and  standard,  each  grade  being 
placed  one  layer  deep  in  broad  flat  trays.  Stacks  of  these 
trays  of  fruit  are  weighed  and  the  proportion  of  the  differ- 
ent grades  credited  to  the  grower  of  the  fruit.  All  through 
washing,  storing,  and  grading  each  grower's  fruit  is  accom- 
panied by  a  ticket  attached  to  the  guide  box.     When  each 


Fig.  117.  —  Lemon  curing  tents  in  p:u'king-housi 


of  several  hundred  growers  has  four  or  five  pickings  in 
greens,  silvers,  and  tree-ripes,  all  in  storage  at  one  time, 
the  task  of  keeping  account  of  each  lot  of  fruit  necessitates 
a  well-organized  system.  In  the  packing-house  lemon 
varieties  are  not  kept  separate,  and  the  name  of  the  variety 
is  not  stenciled  on  the  end  of  the  box  as  is  customary  with 
oranges. 

Lemon  packers  use  the  same  packing  stand  that  is 


310 


Citrus  Fruits 


used  for  oranges,  but  instead  of  packing  from  bins  contain- 
ing fruit  all  of  one  size,  they  pack  from  the  trays,  sizing  the 
fruit  by  eye  and  hand,  the  range  of  sizes  in  each  grade 
running  from  210  to  540  per  box.  Lemons  sizing  300  to 
360  to  the  box  are  in  greatest  demand  on  the  markets, 
Southern  markets  preferring  the  smaller  and  Northern  the 
larger  sizes.  In  one  or  two  of  the  newer  lemon  packing 
houses,  sizing  machines  built  especially  for  lemons  have 


Fig.  118.  —  Truck  for  handling  stacks  of  lemon  trays. 


been  installed.  These  are  operated  very  slowly  in  order 
to  avoid  injury  to  the  fruit.  Most  packers  still  regard 
sizing  machines  for  lemons  with  suspicion. 

The  standard  lemon  box  has  an  outside  measurement  of 
11  by  14-2"  by  27  inches  and  is  divided  in  the  center  by  a 
partition.  For  the  computation  of  freight  charges  a 
box  of  lemons  is  estimated  to  weigh  84  poiuids.  The 
standard  car  of  lemons  contains  312  boxes. 


Picking  and  Packing  Lemons  311 


Fig.  ll'J.  —  Flicking  lemons  from  sorting  trays. 


312  Citrus  Fruits 


Lemons 

Size  Average  Diam- 

eter IN  Inches 

210 23 

240 2| 

270 2i 

300 2| 

360 2i 

420 2i 

490 2 

540 U 

Lemons  were  formerly  shipped  under  ventilation  from 
November  to  March,  and  under  ice  the  remainder  of  the 
year.  Some  shippers  who  have  learned  to  handle  their 
fruit  with  extreme  care  have  abandoned  ice  altogether  to 
their  great  profit.  In  1912-13  only  14  per  cent  of  the 
lemons  shipped  were  iced.  The  average  haul  to  market  is 
2283  miles,  being  304  miles  less  than  the  average  haul 
for  oranges.  This  difference  is  accounted  for  by  the  fact 
that  a  larger  proportion  of  California  lemons  are  marketed 
west  of  the  Missouri  River,  thus  avoiding,  to  a  certain 
extent,  the  sharp  competition  with  Italian  lemons  through- 
out the  Atlantic  seaboard. 

The  freight  rate  on  lemons  from  California  to  New  York, 
Chicago,  and  intermediate  points  has  been  fixed  at  $1.00 
per  hundredweight  after  a  long  and  expensive  contest  in 
the  courts,  the  lemon  growers  finally  winning  their  con- 
tention. 

PICKING    POMELOS    AND    TANGERINES 

Pomelos  are  picked  from  the  middle  of  December  to  the 
following  August  and  many  growers  keep  some  fruit  for 
home  use  on  the  trees  the  year  round.     The  total  ship- 


Picking  and  Packing  Lemons  313 

ment  of  pomelos  from  California  is  not  large,  being  ahont 
200  cars  per  year.  Ordinarily  the  fruit  is  stored  in  lug- 
boxes  for  a  few  days  until  the  rind  becomes  soft  and 
pliable.  After  this  the  fruit  is  packed  in  orange  boxes 
and  handled  like  oranges.  Pomelos  improve  somewhat 
in  flavor  with  storage  and  proper  curing,  and  for  best 
results,  this  fruit  should  be  very  carefully  picked  in 
February  or  March  and  held  in  storage  precisely  as  are 
lemons  until  Mav,  June,  and  July. 


Pomelos 
Size  Average  Diam- 

eter IN  Inches 

04 3| 

80 3§ 

96 3f 

126 31 

150 3 


Large  quantities  of  pomelos  are  grown  in  Florida,  Cuba, 
Porto  Rico,  and  the  Isle  of  Pines,  and  these  dominate 
the  markets  of  the  eastern  United  States.  California 
pomelos  are  marketed  mostly  within  the  state  and  to 
some  extent  in  the  intermountain  country  and  the  Pacific 
Northwest.  Only  a  few  are  sold  in  New  York.  On 
account  of  the  state  quarantine.  Eastern  pomelos  cannot 
be  brought  into  California  for  sale.  At  present  a  large 
portion  of  the  California  pomelos  found  on  the  markets 
are  poor  in  quality.  This  is  due  to  the  fact  that  but  little 
attention  has  been  paid  to  pomelos  and  most  growers 
tend  to  treat  them  in  every  respect  like  oranges.  That 
the  climatic  and  soil  conditions  in  some  parts  of  California 
are  well  suited  for  the  production  of  a  first-class  pomelo 


314 


Citrus  Fruits 


is  evidenced  by  the  fact  that  a  few  skillful  growers  market 
their  fruit  in  New  York  at  very  remunerative  prices  in 
competition  with  Eastern  fruit. 

Tangerines  are  the  only  variety  of  mandarin  orange 
grown  to  any  extent  in  California.  They  are  picked, 
packed,  and  shipped  in  much  the  same  fashion  as  oranges 
except  that,  being  a  fancy  fruit  and  in  limited  demand, 
they  are  not  shipped  in  car  lots.  It  is  customary  to 
market  tangerines  gradually,  including  a  dozen  boxes  or 
half-boxes  in  a  car  of  oranges. 


^&-^c/^-     7=2ai-y//vZ7  //o- 


D- 

-c 

Xx>^ 

^rt 

A             \ 

HHHHtHMHHHHHk 

i  1    i  i 

^^t:cLvy/y^^ 


Fig.  120.  —  Lemon  packing  house.     Compare  with  Fig.  113. 


PACKING-HOUSES 


There  are  hardly  two  packing-houses  in  California  which 
have  the  same  capacity,  arrangement,  or  equipment.  In 
general  the  orange  house  is  small  and  is  equipped  with  a 


Picking  and  Packing  Lemons 


315 


great  deal  of  machinery,  while  the  lemon  honse  is  large 
and  contains  but  little  machinery.  The  fruit  is  received 
at  one  end  from  wagon  scales  and  moves  gradually  through 
the  house  as  it  is  washed,  graded,  sized,  packed,  and  so  on, 
until  the  packed  boxes  are  loaded  on  the  cars  at  the  oppo- 
site end.  Various  types  of  mechanical  conveyors  are  em- 
ployed to  save  labor  in  handlingthe  fruit  and  packed  boxes. 


^^^iwN' 


^^' 


JOiiMSTOlFBOITCO. 


Fu.    IJl  —  Is,  1.  J 


Cleanliness  is  very  important.  No  decaying  fruit 
should  be  allowed  in  the  house,  as  the  spores  given  off 
tend  to  increase  the  amount  of  decay.  All  culls  should 
be  conveyed  by  belt  from  the  grading  table  to  some  bin 
or  outhouse  entirely  separate  from  the  main  packing- 
house and  situated  to  leeward  of  it. 


316  Citrus  Fruits 

The  comfort  of  employees  should  be  provided  for  by 
rest  rooms  and  lunch  rooms.  The  main  packing  floor 
should  be  well  lighted  by  glass  skylights,  for  it  has  been 
found  that  the  efficiency,  comfort,  and  spirit  of  the  em- 
ployees are  greatly  improved  by  clean,  airy,  and  well 
lighted  work-rooms. 


Fig.  122.  —  Combination  box  label. 

Some  packing  associations  confine  their  work  to  packing 
and  shipping,  while  others  take  charge  of  all  picking, 
pruning,  and  in  some  cases  fumigating  of  the  groves. 
In  packing  lemons,  especially,  it  is  a  good  plan  for  the 
packing-house  manager  to  control  the  picking.  The  San 
Dimas  Lemon  Association,  for  instance,  keeps  account 
of  the  fruit  picked  by  each  crew  of  pickers,  and  as  this 


Pick'nuj  (iitd  Pavkinij  Loiwius  317 

fruit  comes  out  of  storage  and  is  sorted  o\er  a  careful 
account  is  kept  of  the  percentage  of  each  kind  of  decay. 
In  this  way  a  check  is  kept  on  the  pickers,  and  if  decay 
due  to  careless  handling  occurs  it  may  be  traced  back  and 
the  blame  placed  where  it  belongs.  Each  foreman  of 
a  picking  crew  knowing  that  he  is  responsible  for  any  decay 
which  may  develop  in  his  lemons  takes  pains  to  instruct 
his  men  in  the  best  methods  of  handling  the  fruit.  At  the 
end  of  each  season  a  substantial  prize  is  awarded  the 
j)icking  crew  in  whose  fruit  the  least  amount  of  decay 
has  developed. 

Pickers  are  drawn  from  many  nationalities.  Americans 
receive  about  $2  a  day,  while  Japanese  and  Hindus  are 
paid  twenty  cents  an  hour.  A  responsible  picking 
foreman  of  considerable  experience  in  handling  lemons  and 
men  may  recei\e  $75  or  more  a  month  aside  from  a 
variable  bonus  at  the  end  of  the  season. 


CHAPTER   XVII 

BLEMISHES  OF  THE  FRUIT  AND  THEIR 
PREVENTION 

A  LARGE  increase  in  the  production  of  citrus  fruits 
will  mean,  if  it  means  anything,  a  keener  competition 
in  the  markets.  In  order  to  meet  this  increased  competi- 
tion, California  growers  and  packers  are  being  encouraged 
to  adopt  higher  ideals  in  grading  and  packing.  With 
more  rigid  grading  the  cull-heaps  near  many  of  the 
packing-houses  assume  large  proportions.  A  conserva- 
tive estimate  places  the  direct  loss  from  cull  oranges 
alone,  aside  from  frozen  fruit,  in  excess  of  a  half-million 
dollars  a  year. 

It  is  well  worth  while,  therefore,  to  make  a  study  of  the 
cull-heap,  classifying  and  determining  the  relative  im- 
portance of  the  various  blemishes  which  cause  oranges 
to  be  thrown  into  a  lower  grade  or  into  the  cull-heap.  We 
will  also  consider  how  far  it  is  practicable  and  by  what 
means  the  proportion  of  culls  to  packed  fruit  may  be 
reduced. 

The  blemishes  of  citrus  fruits  may  be  classified  according 
to  their  causes.  For  convenience  we  may  group  them 
under  four  heads,  namely :  insect,  fungus,  mechanical, 
and  physiological  blemishes. 

318 


Blemishes  of  the  Fruit  and  their  Prevention       319 

As  a  result  of  counts  of  Navel  culls  made  in  twelve 
packing-houses  during  January  and  February,  1910  and 
1911,  it  appears  that  on  the  average,  the  most  prolific 
causes  of  culls  are  as  follows,  according  to  their  impor- 
tance :  splits,  bruises,  thorn  stabs,  thrips  scars,  sunburns, 
and  worm  holes.  These  six  kinds  of  blemishes  are  re- 
sponsible for  upwards  of  seventy-five  per  cent  of  the 
culls.  These  counts,  however,  did  not  take  into  consid- 
eration the  brown  spot  which  usually  does  not  develop 
until  the  fruit  has  left  the  packing-house. 


INSECT    BLEMISHES 

Insect  pests  and  their  control  will  be  discussed  rather 
fully  in  Chapter  XXII  and  it  is  only  necessary  here  to 
name  those  blemishes  of  the  fruit  which  are  due  to  insects. 
They  are  :  thrips  scars  ;  tortrix  worm  holes  ;  scale  insects 
such  as  red,  yellow,  purple,  and  the  sooty  mold  which 
follows  and  grows  upon  the  excretions  of  the  black,  gray, 
and  brown  scales  ;  mealy  bugs  ;  red  spiders  ;  silver  mites ; 
grasshoppers  ;  katydids  ;   and  some  others. 

The  presence  of  a  few  scale  insects  on  fruit  intended 
for  some  markets  in  the  East  need  not  condemn  it,  but 
there  are  other  markets,  such  as  certain  ones  in  British 
Columbia,  where  inspectors  condemn  all  scaly  fruit  even 
though  citrus  fruits  be  not  grown  in  the  region. 


FUNGUS    BLEMISHES 

The  fungi  which  produce  injury  to  the  fruit  are  :  brown 
rot,    Pythiacysiis   citrophthora;     blue    mold,    Penicillium, 


320  Citrus  Fruits 

italicum;  green  mold,  PeniriUinm  digitatnm;  gray  mold, 
Botrytis  cinerea;  sooty  mold,  Meliola  cameUicF ;  cottony 
mold,  Sclcrotinia  libertifuia ;  gray  scurf,  fungus  not  as 
yet  identified;  wither-tip,  CoIIctotrichum  gloeosporioides; 
black  rot  of  the  Navel,  AUernaria  citri;  and  stem-end 
spot,  Cladosporium  sj).  (secondary). 

Most  of  the  fungus  diseases  which  cause  blemishes  on 
the  fruit  result  in  complete  loss.  The  nature  of  these 
diseases,  together  with  control  measures,  will  be  discussed 
in  detail  in  Chapter  XXI. 

The  fungus  causing  gray  scurf  or  scab  on  lemons  has 
not  as  yet  been  identified.  The  fungus  apparently  acts  as 
a  secondary  agent;  the  primary  cause  is  probably  the 
slight  bruising  of  the  young  tender  fruit  by  the  wind. 
The  best  remedy  for  this  trouble  is  the  growing  of 
windshields  and  close  planting  of  the  lemon  trees.  By 
proper  pruning  also  the  branches  may  be  made  stiffer 
and  more  resistant  to  the  swaying  and  whipping  effect 
of  the  wind. 

The  stem-end  spot  of  oranges  is  a  very  different  thing 
from  stem-end  rot,  and  occurs  mostly  on  Navels  and 
on  fruit  which  has  hung  late  on  the  trees.  It  consists 
of  a  breaking  down,  browning,  and  shrinking  of  the  skin 
in  certain  small  spots  near  the  stem.  Ordinarily  this 
causes  little  injury,  but  occasionally  during  rainy  weather 
a  species  of  Cladosporium  grows  on  the  dead  tissue  of 
these  spots,  giving  them  a  black  color  which  detracts 
very  much  from  the  appearance  of  the  fruit.  The  only 
remedy  at  present  available  for  this  trouble  is  to  pick 
the  fruit  earlv  in  those  orchards  where  the  trouble  becomes 


Blemishes  of  the  Fruit  and  their  Prevention       321 


MECHANICAL    BLEMISHES 

Much  otherwise  good  fruit  is  ruined  by  carelessly  in- 
juring tlie  fruit  mechanically.  Growers  and  packing-house 
men  rarely  realize  how  serious  are  the  losses  resulting 
from  such  causes. 

Bruises.  —  Fruit  which  is  bruised  by  careless  handling 
is  almost  sure  to  decay.  Careful  handling  should  be  the 
cardinal  principle  of  every  picker  and  packer.  When  a 
stack  of  boxes  of  fruit  is  accidentally  overturned  in  the 
packing-house,  the  fruit  should  be  set  aside  for  ten  days 
and  then  sorted  over,  the  decaying  fruit  being  eliminated. 

Thorn  stabs.  —  ]\Iuch  fruit  is  ruined  by  thorns.  In  wet 
weather  such  thorn-pricked  fruit  decays,  but  in  dry 
weather  the  broken  skin  may  cauterize  and  result  in  a  spot. 
Sometimes  a  fruit  continually  swinging  against  a  thorn 
will  develop  a  thick  horny  rind  at  that  point,  which  ruins 
its  appearance.  Thornless  varieties,  careful  pruning,  and 
windbreaks  are  the  remedies. 

Cultivator  scars.  —  Cultivators  and  other  tillage  im- 
plements should  be  covered  by  a  smooth  tin  shield  which 
will  allow  low-hanging  fruit  to  slide  over  them  without 
injury.  ]\Ietal  projections  on  harness  are  also  objection- 
able. When  it  is  necessary  to  cultivate  close  up  under 
the  trees  a  great  deal  of  fruit  will  be  ruined  unless  pro- 
tected by  some  sort  of  shield  attached  to  the  implements. 

Clipper  cuts.  —  When  the  use  of  pointed  clippers  was 
in  vogue  the  loss  from  clipper  cuts  was  very  great.  Now, 
however,  round  pointed  clippers  are  used,  and  there  is  no 
excuse  for  clipper-cutting  the  fruit. 

Stem  punctures.  —  When  the   stems  are   not  properly 


322 


Citrus  Fruits 


cut  off  square  and  close,  they  puncture  a  great  deal  of 
fruit  in  the  box,-  and  as  they  pass  through  the  packing- 
house machinery.  A  close  watch  kept  on  the  pickers 
should  prevent  this. 

Machine  injuries.  —  Some  years  ago  a  certain  packing- 
house foreman  complained  of  excessive  decay  which  could 
not  be  explained.  Finally  one  of  the  employees  dis- 
covered a  loose  screw  in  one  of  the  guide  bars  of  the 
brushing  machine  hopper.  The  sharp  head  projected  an 
eighth  of  an  inch  and  made  a  little  nick  in  every  orange 
which  rolled  by.  Passing  over  the  brushes  each  nick 
was  thoroughly  inoculated  with  decay  germs.  The  guilty 
screw  head  was  driven  home,  after  which  the  decay  in 
transit   dropped   from   35   per  cent  to  4  per  cent.     The 

remedy  for  this  is  to 
keep  a  close  watch 
for  screw  heads  or 
splinters  on  all  ma- 
chinery and  for  pro- 
jecting nails  in  field 
boxes. 

Fumigation  scars.  — 
Oftentimes  fruit  is 
pitted  and  burned  by 
carelessly  overdosing 
trees  with  gas  during 
fumigation.  Fumiga- 
tors  should  be  held  re- 
sponsible for  such  in- 
jury. Occasionally,  however,  it  happens  that  a  sudden 
change  in  the  weather  or  condition  of  the  atmosphere 


Fig.  123.  —  Fumigation  scars. 


Blemishes  of  the  Fruit  and  their  Prevention       323 


will  result  in  wholesale  pitting  of  fruit  even  with  the  same 
dosage  which  was  harmless  a  few  hours  earlier.  No 
remedy  has  been  found  for  this  difficulty,  and  fumigators 
are  not  to  blame.     Fortunately  such  occurrences  are  rare. 

Shoulder  spots.  —  Where  two  oranges  grow  touching 
each  other  the  point  of  contact  is  often  shown  by  a  light 
colored  area  with  a  reddish  spot  in  the  center.  Such 
spots  are  not  very  serious  and  cannot  be  remedied  unless 
the  fruit  be  thinned.  Thinning  citrus  fruits  has  never 
been  practiced  in  California. 

Hail  scars.  —  Hail  storms  are  of  rare  occurrence  in  the 
citrus  districts.  When  they  do  occur  they  pit  the  fruit. 
If  the  hail  is  followed  by  dry  weather,  most  of  the  pits  will 
dry  and  little  injury  will  result.  In  wet  weather,  however, 
some  fruit  will  de- 
cay on  the  tree 
with  blue  or  green 
mold,  while  in  some 
cases  a  species  of 
Cladosporium  will 
grow  on  the  pits  and 
turn  them  black  in 
color. 

Soil  scars.  —  Where 
heavy  crops  of  fruit 
bend  the  branches 
down  much  fruit  often 
rests  on  the  ground. 
When  the  wind  moves 
the  branches  the  rubbing  of  the  fruit  on  the  ground 
causes  a  gray  callous  spot  which  ruins  its  appearance. 


Fig.  124. 


Sear  caused  by  nibbing  on  the 
ground. 


324  Citrus  Fruits 

JVindf aJ Ls. —  OccsisionaWy  strong  winds  will  whip  a 
large  part  of  the  orange  crop  from  the  trees,  as  was  the  case 
in  September,  1911.  It  is  rarely  safe  to  send  a  windfall 
to  the  packing-house,  as  it  is  very  apt  to  develop  decay. 

Cement  dust.  —  In  certain  localities  the  fruit  is  coated 
on  the  upper  side  with  a  crust  of  cement  dust  which  comes 
from  near-by  cement  mills.  This  dust  collects  in  the 
pores  of  orange  skin  and  sets,  being  very  difficult  to 
remove.     It  injures  the  appearance  and  reduces  the  grade. 

PHYSIOLOGICAL    BLEMISHES 

This  class  of  blemishes  is  not  only  large  and  the  losses 
serious  but  the  causes  are  as  a  rule  not  well  understood. 
The  total  number  of  troubles  of  this  kind  is  very  large 
and  new  ones  are  continually  appearing.  Only  the  most 
important  will  be  mentioned  here. 

Sunburn.  —  Both  oranges  and  lemons  which  hang  fully 
exposed  to  the  sun  are  often  injured.  The  exposed  side 
becomes  dwarfed  in  growth,  resulting  in  malformation, 
and  the  skin  of  oranges  becomes  thick  and  pale  colored 
and  adheres  tightly  to  the  flesh.  In  interior  valleys  where 
the  sun  is  very  hot  the  skin  may  die  and  a  hard  black  spot 
result.  In  such  situations  the  trees  should  be  pruned  in 
such  a  way  as  to  encourage  the  production  of  inside  fruit, 
which  is  always  much  finer  in  appearance.  Lemons  are 
often  noticed  in  the  markets  which  are  lop-sided,  the  dis- 
tance from  stem  to  apex  being  greater  on  one  side  than  the 
other.  This  is  caused  by  shght  sunburn  and  is  a  sure 
sign  that  the  lemon  grew  in  an  exposed  position  on  the 
tree.     There  is  a  curing  house  trouble  of  lemons  known  as 


Blemishes  of  the  Fruit  and  their  Prevention       325 

red  rot,  or,  more  properly,  red  blotch,  which  develops  as 
a  rusty  brown  color,  gradually  drying  down  into  a  sunken 
condition  with  a  dark  red  or  black  color.  This  has  been 
attributed  to  sunburn,  as  it  is  most  common  in  lemons 
from  exposed  parts  of  the  trees. 

Frost.  —  The  losses  from  frost  are  of  course  very  large, 
but  many  fruits  are  only  slightly  frosted,  and  while  they 
should  be  packed  under  a  frost  label  they  are  good  for 
consumption.  Oranges  usually  exhibit  no  outward  signs 
of  frost  unless  severely  frozen.  Occasionally,  however, 
certain  oranges,  especially  those  having  more  or  less  thick 
skins  and  growing  low  down  on  the  north  side  of  the  tree 
will  show  a  number  of  characteristic  brownish  spots  on  the 
exposed  side  even  though  but  slightly  frosted. 

Off-bloom.  —  Occasionally  orange  and  pomelo  trees  will 
blossom  out  of  their  regular  season.  The  cause  of  this 
is  not  always  apparent,  although  it  is  often  due  to  irregu- 
larities in  irrigation.  Fruits  developing  from  off -blooms 
are  usually  malformed  and  inferior.  Navel  off-blooms 
produce  fruits  with  sunken  instead  of  protruding  navels. 
Pomelo  off-blooms  produce  fruits  which  are  distinctly 
pear-shaped  as  compared  with  the  regular  crop.  Regu- 
larity and  thoroughness  of  irrigation  and  cultivation  will 
reduce  the  amount  of  off-bloom  fruit  to  a  negligible 
quantity. 

Mottled-leaf.  —  This  disease  is  not  at  present  well 
understood.  It  results  in  the  production  of  very  small 
oranges  and  lemons  of  a  whitish  color,  often  quite  unfit 
for  packing.     (See  Chapter  XXI.) 

E.ranthema.  —  This  trouble  appears  on  the  fruit  as  dark 
reddish  blotches  or  crusts.     In  severe  cases  the  fruit  is 


326  Citrus  Fruits 

dwarfed  in  growth  and  cracks  open  on  the  trees.  (See 
Chapter  XXL) 

Malformation. —  Many  kinds  of  malformations  are 
common.  They  may  be  divided  into  two  classes  :  those 
due  to  sporting  such  as  corrugations  and  color  stripes  of 
the  rind,  bottled-necked  fruits,  and  others,  which  may  be 
remedied  by  pruning  out  all  of  the  sporting  branches ; 
and  those  due  to  an  excess  of  food  and  teratological  factors. 
Many  Navel  oranges,  especially  those  borne  on  the  top- 
most branches,  exhibit  a  double  or  proliferated  navel. 
Often  this  takes  the  form  of  a  small  secondary  orange 
superimposed  upon  the  navel.  These  are  very  common 
and  are  always  thrown  into  the  cull-heap  because  the 
small  orange  would  have  to  be  broken  off  before  packing 
and  this  would  result  in  decay.  Often  twin  oranges 
partly  attached  are  met  Avith  which  are  discarded  for  the 
same  reason.  The  fruit  borne  near  the  large  upright 
central  branches  often  has  coarse,  grooved  skin  about  the 
stem.  This  is  caused  apparently  by  the  superabundance 
of  food  and  may  be  largely  prevented  by  proper  pruning. 

Broum  spot.  —  The  brown  spot  of  the  Navel  orange  may 
be  described  as  occurring  irregularly  over  the  surface  of 
the  orange.  From  one  to  fifty  or  more  spots  may  develop 
on  a  single  fruit.  The  spots  vary  in  size  from  a  mere 
point  to  one  inch  in  diameter,  averaging  about  one-fourth 
inch. 

This  brown  spot  occurs  only  on  the  Navel  oranges,  and 
is  uniformly  worse  on  fancy,  smooth,  thin-skinned  fruit. 
The  total  money  loss  from  this  particular  spot  is  very 
large.     For  further  particulars  see  Chapter  XXI. 

Cracks  and  splits.  —  Cracks  differ  from  splits  in  being 


Blemishes  of  the  Fruit  and  their  Prevention       327 

transverse  rather  than  longitudinal  openings  in  the  rind 
of  the  orange.  They  are  of  rare  occurrence  and  their 
cause  is  unknown.  Splits,  on  the  other  hand,  are  very 
common  and  cause  heavy  losses,  especially  with  Navel 
oranges   in   interior  valleys.     Splits   are   of   two   kinds : 


Fig.  125.  —  Orange  splits.     Side  splits  above  and  navel-end  splits  below. 


side  splits  and  navel  splits.  Side  splits  are  caused 
by  teratological  cavities  or  seams  in  the  skin.  Thus 
weakened  the  skin  is  unable  to  withstand  the  growth 
pressure,  and  a  split  results. 

A  Navel  orange  which  is  split  even  a  fourth  of  an  inch  at 
the  navel  must  not  be  packed  for  long  distance  shipment,  for 
such  an  opening  is  almost  sure  to  be  inoculated  with  decay. 


328 


Citrus  Fruits' 


All  such  oranges  must  be  graded  out  but  may  often  be  sold 
to  local  peddlers  for  enough  to  pay  for  picking  and  hauling. 
The  most  common  theory  in  regard  to  the  cause  of  splits 
is  that  an  irregular  water  supply,  causing  wide  variations 
in  the  moisture  content  of  the  soil,  produces  a  greater 
fluctuation  in  the  growth  of  the  interior  than  in  the  skin 
of  the  orange.  Such  a  theory  is  quite  reasonable,  but  such 
a  cause  should  be  regarded  as  contributory  only,  inasmuch 

as  only  a  part  of  the 
fruit  on  any  given  tree 
will  split.  If  a  number 
of  navel-split  oranges  are 
cut  in  longitudinal  sec- 
tions, it  will  be  found, 
almost  without  excep- 
tion, that  the  thickness 
of  the  rind  varies,  being 
quite  thick  and  often 
creased  at  the  stem  end, 
and  as  thin  as  paper  near 
the  navel.  Specimens 
with  uniform  thickness 
of  skin  very  rarely  split. 
Hot,  dry  spells  of  weather 
alternating  with  damp  cloudy  weather,  together  with  careless 
irrigation,  cause  a  high  percentage  of  spHts  among  this  class 
of  oranges.  While  much  may  be  done  toward  overcoming 
this  loss  by  careful  irrigation  and  cultivation,  the  most 
important  remedy  is  probably  the  propagation  of  trees 
from  carefully  selected  bud-wood.  By  this  means  we 
may  largely  eliminate  from  our  future  orchards  the  un- 


FiG.  126.  —  Horizontal  cracks  are  very 
different  from  splits. 


Blemishes  of  the  Fruit  and  their  Prerention 


.329 


desirable  types  which  are  so  prone  to  split  during  un- 
favorable weather. 

Puffing.  —  When  oranges  are  left  too  long  on  the  trees, 
they  will  often  become  puffy.  The  rind  becomes  weak, 
with  many  cross  creases  and  much  unevenness.  Finally 
the  whole  orange 
becomes  soft  and 
structureless.  The 
walls  of  the  juice 
vesicles  become  much 
thickened  and  the 
juice  partly  disap- 
pears, leaving  the 
fruit  dry,  crumbly, 
and  insipid.  The 
remedy  for  this 
trouble  is  to  pick  the 
fruit  earlier  in  those 
localities  where  putt- 
ing is  serious. 

Petec  a.— This 
trouble  appears  in 
the  form  of  deep 
sunken  pits  in  the 
rind  of  lemons  after  they  have  been  in  the  curing  house 
for  some  time.  The  tissue  at  these  spots  is  found  to 
be  dried  and  shrunken  prematurely,  somewhat  after  the 
fashion  of  the  brown  spot  of  the  Navel  orange.  The 
cause  of  peteca  is  not  known. 

Dry  center  of  lemon.  —  Ps.  peculiar  trouble  which  has  be- 
come quite  general  in  recent  years.     The  vesicles  collapse 


330  Citrus  Fruits 

in  groups,  turn  brown,  and  dry  up.  Injury  is  always 
greatest  near  the  blossom  end  and  is  often  accompanied 
by  germination  of  the  seeds  while  still  within  the  fruit. 
In  advanced  cases  the  interior  of  the  lemon  may  become 
filled  with  a  mass  of  roots  from  the  seeds.  While  this 
trouble  results  in  a  loss  of  juice,  the  housewife  who  cuts 
the  lemons  through  the  center  is  not  apt  to  discover  their 
inferiority  as  there  is  little  surface  indication  of  dry  center. 
In  many  ways  this  trouble  resembles  bitterpit  of  the 
apple.  At  present  neither  the  cause  nor  a  remedy  is 
known. 


CHAPTER   XVIII 
BY-PRODUCTS 

Until  very  recently  it  has  been  the  custom  in  Cahfornia 
to  haul  the  cull  fruits  from  the  packing-houses  and  dump 
them  in  waste  places.  A  very  few  growers  returned  the 
culls  to  the  orchards  and  plowed  them  into  the  soil  for 
the  sake  of  their  humus  value  and  the  small  amount  of 
plant-food  they  contain.  But  the  bulk  of  the  culls  have 
been  thrown  away,  and  when  we  consider  the  enormous 
waste  resulting  from  this  practice  the  question  arises  as  to 
whether  a  part  at  least  of  this  large  tonnage  of  fruit  may 
not  be  profitably  converted  into  valuable  by-products. 

That  citrus  by-products  are  in  strong  demand  in  the 
United  States  is  proved  by  our  annual  importation  of 
these  items  from  abroad.  The  imports  of  the  year  1909 
are  fairly  typical  of  other  years  and  are  given  on  page 
332.  The  values  given  are  the  appraised  wholesale  values 
at  the  port  of  export  and  would  be  considerably  higher 
if  appraised  in  this  country. 

At  the  present  time  nearly  all  citrus  by-products  are 
produced  in  Europe,  while  small  amounts  come  from 
Paraguay,  China,  and  California. 

The  chief  reason  why  citrus  by-products  have  not  been 
more  largely  produced  in  the  United  States  is  that  the 
331 


332 


Citrus  Fruits 


cost  of  labor  is  from  three  to  five  times  greater  tlian  in  the 
citrus  producing  regions  of  Europe.  At  })resent,  however, 
there  is  a  widespread  interest  in  this  subject  in  CaHfornia. 
Several  small  factories  are  already  in  operation,  and  several 
more  are  in  process  of  construction. 

Importation    of    Citrus    By-products    into    the    United 
States  for  the  Year  ending  June  30,  1909 


Quantity 

Value 

Citric  acid  —  lb 

Citrate  of  lime  —  lb 

Lemon,  lime,  and  sour  orange  juice 
Orange  and  lemon  peel  not  candied, 

preserved,  or  dried 

Citron  or  citron  peel,  candied  or  dried 

—  lb 

Citron  preserved  in  brine  —  lb.      .     . 
Orange   and   lemon   peel,    preserved, 

candied,  or  dried  —  lb 

Oil  of  bergamot  —  lb 

Lemon  oil  —  lb 

Lime  oil  —  lb 

Oil  of  neroli  or  orange  flower  —  lb. 
Orange  oil  —  lb 

243,010 
3,917,274 

991,341 
4,075,835 

436,129 
89,957 

405,695 
21,991 
23,184 
87,591 

.S74,209 

489,031 
81,386 

4,833 

79,519 
100,224 

20,692 
281,211 
358,197 
9,973 
170,342 
151,860 

Total 

.Sl,821,477 

In  Europe  the  citrus  by-product  industry  is  largely 
centered  on  the  Island  of  Sicily  and  in  Calabria.  In 
these  districts  the  two  chief  products  are  citric  acid  and 
lemon  oil.  About  one-third  of  the  total  lemon  crop  of 
this  region  is  consumed  in  the  manufacture  of  citrate  of 
lime,  and  from  the  peel  of  these  same  lemons   comes  the 


By-Products  333 

enormous  quantity  of  essential  oil,  or  essence  of  lemon, 
which  furnishes  practically  the  world's  supply. 


COMMERCIAL    BY-PRODUCTS 

For  convenience  those  by-products  at  present  manu- 
factured on  a  commercial  scale  will  be  grouped  separately 
from  a  number  of  domestic  recipes  which  are  included. 
Several  of  the  products  described  under  domestic  recipes 
may  of  course  be  produced  on  a  commercial  scale,  should 
the  demand  warrant. 

Citric  acid.  —  Citric  acid  is  manufactured  from  the  juice 
of  the  lemon  chiefly,  although  lime  juice  is  used  to  some 
extent.  The  peel  is  first  removed  and  used  for  the  pro- 
duction of  lemon  and  lime  oil  which  will  be  described  later. 
The  lemons  are  halved  and  the  pulp  scooped  out  with  a 
sharp  spoon.  The  pulp  is  then  passed  through  toothed 
cylinders  which  shred  it,  and  the  juice  is  extracted  from 
the  mass  by  a  high  power  press.  The  crude  juice  con- 
tains water  in  abundance,  citric  acid,  malic  acid,  several 
kinds  of  sugar,  albuminoids,  and  mucilage.  The  crude, 
juice  is  filtered,  placed  in  boilers,  and  heated  nearly  to  the 
boiling  point.  Finely  powdered  chalk,  mixed  to  a  cream 
in  water,  is  slowly  added,  while  the  hot  liquid  is  being 
constantly  stirred.  The  chalk  or  carbonate  of  lime 
unites  with  the  citric  acid,  forming  calcium  citrate,  which 
is  insoluble  and  precipitates  from  the  juice  as  a  white 
powder,  which  is  collected,  washed,  and  dried  into  cakes. 
Great  care  is  used  to  add  just  enough  chalk  to  take  up 
the  citric  acid  as  shown  by  litmus  tests.  As  citric  acid 
must  pay  a  duty  of  seven  cents  a  pound  on  entering  the 


334  Citrus  Fruits 

United  States  and  citrate  of  lime  is  free,  most  of  the  Italian 
product  is  shipped  to  this  country  as  citrate  of  lime,  and 
the  final  step  in  the  process  is  completed  in  this  country. 
This  final  step  consists  in  treating  the  citrate  with  dilute 
sulphuric  acid,  which  forms  svilphate  of  lime  and  leaves 
citric  acid  in  solution.  This  solution  is  evaporated  in 
leaden  boilers  until  the  pure  citric  acid  crystallizes  out, 
and  is  washed  and  dried.  Citrate  of  lime  contains  about 
65  per  cent  of  citric  acid. 

Lemon  oil,  orange  oil,  bergamot  oil,  and  lime  oil.  —  The 
peel  of  all  citrus  fruits  is  thickly  dotted  with  small  glands 
yielding  an  essential  or  highly  volatile  oil.  The  oils 
from  the  different  kinds  of  citrus  differ  considerably  in 
their  characteristics.  These  oils  are  in  great  demand 
for  flavoring  extracts  and  perfumery,  and  the  demand 
for  the  different  kinds  is  in  the  order  given.  Of  these, 
lemon  oil  is  used  in  much  the  largest  quantities.  Any 
person  may  easily  demonstrate  the  presence  of  this  vola- 
tile oil  by  squeezing  a  piece  of  fresh  peel  in  such  a  way 
as  to  cause  the  oil  to  spurt  out  into  the  flame  of  a  lighted 
match.  It  will  burn  with  a  flash,  showing  its  high  vola- 
tihty. 

The  major  part  of  the  oils  now  on  the  market  come  from 
Sicily  and  Calabria.  The  contrivances  for  extracting  the 
oil  are  very  crude,  much  hand  labor  being  necessary. 
As  before  stated,  the  fact  that  labor  in  Italy  costs  only 
one-third  as  much  as  in  California  is  the  chief  reason  why 
California  has  not  produced  a  larger  amount  of  citrus  oils. 

After  the  pulp  has  been  removed  from  the  halved  lemons 
and  pressed  for  citrate,  the  peels  are  soaked  in  cold  water 
for  a  few  hours  to  increase  the  turgidity  of  the  cells.     They 


By-Products  335 

are  then  taken  by  men  who  press  out  the  oil  entirely  by 
hand.  The  pressers  sit  on  low  stools  with  a  small  lipped 
bowl  between  their  feet.  Across  the  top  of  the  bowl 
rests  a  strong  notched  stick  which  supports  a  large  sponge. 
Each  half  lemon  is  placed  against  the  sponge  and  given 
three  or  four  sharp  squeezes,  using  almost  the  entire  weight 
of  the  body.  The  oil  spurting  out  of  the  peel  is  caught  by 
the  sponge  and  drips  through  it  into  the  bowl  below. 
From  time  to  time  the  bowl  is  raised  and  the  oil  is  blown 
off  by  the  breath  into  a  graduated  glass  receptacle,  the 
lip  retaining  the  small  amount  of  water  and  residue. 
After  the  oil  is  filtered  through  a  paper  filter  it  is  ready  for 
market.  In  (^alabria  a  crude  machine  is  used  in  which  is 
a  bowl  lined  with  sharp  metal  points.  The  fruit  is  placed 
whole  in  this  bowl  and  revolved,  the  points  puncturing 
the  peel,  from  which  the  oil  drips  through  an  opening  in 
the  bottom  of  the  bowl.  This  device  is  called  an  ecuelle, 
and  is  used  chiefly  in  the  making  of  bergamot  oil,  for  the 
reason  that  bergamot  oranges  are  round  in  shape  and 
revolve  to  better  advantage  in  the  machine. 

Some  few  operators  lacerate  the  rinds  of  lemons  or 
oranges  and  distill  the  oil,  but  the  use  of  this  method 
results  in  water  white  oil  of  very  inferior  grade. 

A  large  amount  of  oil  of  limes  is  made  in  the  West 
Indies.  The  oil  is  extracted  from  whole  fruit  by  hand 
in  ecuelle  pans,  the  pulp  being  later  pressed  and  the  juice 
concentrated  by  evaporation  and  sold  as  lime  juice  to  be 
used  as  a  drink. 

Uufermenied  orange  juice.  —  "  A  very  palatable  and 
attractive  beverage  can  be  made  from  oranges.  The 
chief  difficulty  is  the  mechanical  one  of  rapidly  and  eco- 


336  Citrus  Fruits 

nomically  separating  the  juice  from  the  solid  parts  of  the 
fruit.  The  juice  can  easily  be  made  perfectly  and  per- 
manently clear  by  settling  and  filtration.  Sulfurous  acid 
in  very  small  amounts  (4  ounces  potassium  metabisulfite 
to  100  gallons  of  juice,  an  amount  well  below  the  limit 
allowed  by  law)  is  necessary  to  prevent  fermentation  and 
the  production  of  a  bitter  taste  during  setthng.  The 
cleared  juice  keeps  perfectly  after  bottling  if  pasteurized 
at  180°  F.,  which  does  not  injure  the  flavor  perceptibly. 
Good  oranges  will  yield  over  1 30  gallons  per  ton ;  frozen 
oranges  a  much  less  amount."  ^ 

Orange  oil,  for  which  there  is  a  good  demand,  may  be 
extracted  from  the  skins  of  the  oranges  used  in  the  manu- 
facture of  juice. 

Orange  vinegar.  —  A  good  quality  of  vinegar  may  be 
manufactured  from  the  juice  of  cull  oranges  w4iich  are 
well  matured  and  have  a  total  sugar  content  of  10  per 
cent  or  more.  Cruess  ^  has  shown  that  orange  juice  con- 
taining 11  per  cent  will,  on  fermentation,  give  about  5.5  per 
cent  of  alcohol,  and  that  this  on  conversion  into  acetic 
acid  will  yield  about  5.5  per  cent  of  acid,  which  is  consid- 
erably over  the  legal  limit  of  4  per  cent  of  acetic  acid. 

Inasmuch  as  many  samples  of  orange  juice  may  be 
expected  to  contain  9  per  cent  or  less  of  total  sugars,  it  is 
apparent  that  the  resulting  vinegar  will  closely  approach 
or  even  fall  below  the  legal  limit  unless  considerable  care 
be  used  in  the  selection  of  the  raw  material  as  well  as  in 
the  fermentation  process. 

^  W.   V.    Cruess,     "Utilization   of    Waste   Oranges,"    Calif. 
Exp.  Sta.,  Bull.  No.  244,  1914. 
2  Ibid.,  p.   164. 


Bij-Prodnrts  337 

Orange  icine.  —  IMost  of  the  so-called  orange  wines  found 
on  the  markets  are  made  from  orange  juice  flavored  with 
orange  oil,  fortified  by  the  addition  of  alcohol  or  brandy, 
and  sweetened  by  the  addition  of  sugar  or  sirup.  Such 
liquids,  of  course,  have  no  right  to  be  called  orange  wine. 

An  agreeable  pure  orange  wine  can  be  made  by  the  use 
of  proper  methods.  Such  methods  consist  in  "  defecating 
the  fresh  juice  after  the  addition  of  moderate  amounts  of 
potassium  metabisulfite  to  prevent  fermentation  for  a 
short  time,  fermenting  the  clear  juice  with  pure  yeast, 
and  filtering  the  finished  wine  to  clear  it.  This  cleared 
wine  may  be  turned  into  sparkling  orange  wine  by  the 
addition  of  a  small  amount  of  sugar  and  by  subsequent 
fermentation  in  bottles."  ^ 

Candied  citron.  —  JNIost  of  the  citron  consumed  in  the 
United  States  comes  from  the  Mediterranean  region  and 
especially  from  the  Island  of  Corsica.  The  chief  reason 
why  citron  is  not  more  largely  produced  in  California  is 
the  difference  in  the  cost  of  labor.  Citron  is  admitted  to 
the  United  States  from  Corsica  duty  free  when  it  is  shipped 
pickled  in  brine  or  ordinary  sea  water.  Practically  all 
imported  citron  is  candied  in  this  country.  There  is  one 
firm  now  engaged  in  the  growing  and  processing  of  citron 
near  Riverside,  California. 

The  fruit  as  it  first  begins  to  assume  a  bright  yellow  color 
is  picked  and  placed  in  brine  for  a  month  or  longer,  the 
brine  being  renewed  occasionally.  Sometimes  tender 
young  leaves  of  the  citron  tree  are  soaked  with  the  fruit 
to  deepen  the  green  color.  The  fruit  is  then  boiled  in 
fresh  water  to  remove  the  salt  and  soften  it.  It  is  then 
1  Ibid.,  p.  170. 


338  Citrufi  Fruits 

halved,  the  pulp  and  seed  scooped  out,  and  immersed  in 
cold  fresh  water  to  intensify  the  greenish  color.  After 
this  it  is  covered  with  hot  sugar  sirup  and  allow^ed  to 
stand  three  or  four  weeks,  during  which  time  the  strength 
of  the  sirup  is  gradually  increased.  The  fruit  is  then 
put  into  boilers  with  crystallized  sugar  sirup  and  cooked  ; 
then  allowed  to  cool,  more  sugar  is  added,  and  it  is  cooked 
again  until  it  will  take  up  no  more  sugar.  It  is  then  dried 
and  packed  in  wooden  boxes,  each  piece  being  coated  with 
white  sugar  crystals  and  wrapped  in  tissue  paper. 

Oil  of  neroli.  —  This  product  is  made  chiefly  in  the  vicin- 
ity of  Grasse  in  the  French  Riviera.  Neroli  is  made  by 
distilling  the  flowers  of  the  bitter  or  bigarade  orange, 
known  in  California  as  sour-stock.  Both  oil  and  water 
pass  through  the  still ;  and  as  they  condense  the  oil  col- 
lects on  the  surface,  is  skimmed  off,  and  sells  for  a  very  high 
price  (from  $20  to  $50  a  pound).  Three  hundred  pounds 
of  flowers  are  required  to  make  one  pound  of  neroli.  The 
water  which  distills  over  absorbs  some  perfume  from  the 
oil  and  is  sold  as  eau  de  fleur  d'oranges,  bringing  about 
twenty-five  cents  a  gallon. 

Petit  grain  oil.  —  This  oil  is  used  in  perfumery  and  is 
prepared  by  distilling  the  young  and  tender  leaves  and 
shoots  of  both  bitter  and  sweet  oranges.  It  sells  for  from 
two  to  five  dollars  a  pound.  A  large  part  of  the  petit 
grain  oil  now  comes  from  Paraguay,  where  orange  trees 
have  run  wild  and  occur  in  forests  over  a  large  area. 

Tincture  of  orange  flowers.  —  This  is  a  perfume  which 
is  prepared  by  steeping  the  fresh  flowers  in  alcohol  until 
all  the  perfume  has  been  absorbed  by  the  alcohol. 

Essence  of  orange  flowers.  —  This  perfume  is  produced 


Bij-ProHncts  1^39 

in  large  quantities  in  Europe  and  imported  into  this 
country.  Apparently  there  is  no  reason,  except  the  high 
cost  of  labor,  to  account  for  the  lack  of  production  in  the 
United  States.  As  orange  trees  produce  many  times  the 
number  of  flowers  that  are  needed  for  setting  a  crop,  and 
most  of  them  fall  off  normally,  the  preparation  of  essence 
need  not  hinder  fruit  bearing.  The  making  of  the  per- 
fume is  a  simple  matter,  and  the  preparation  of  a  small 
supply  for  home  use  might  furnish  a  pleasing  i)astime  for 
young  people  living  among  orange  groves.  In  the  early 
morning  orange  blossoms  are  collected  as  soon  as  the  petals 
begin  to  fall,  by  shaking  the  tree  over  a  sheet  spread  on  the 
ground.  A  tree  yields  from  two  to  ten  pounds  of  flowers. 
The  perfume  is  generally  extracted  by  enfleurage.  Shal- 
low trays  containing  layers  of  fresh  blossoms  are  slipj)ed 
into  the  grooved  sides  of  a  large  air  tight  box.  The  box 
is  filled  Avith  trays,  but  between  each  two  trays  is  inserted 
a  sheet  of  wire  gauze  or  linen  holding  a  thin  layer  of  wax 
or  mixed  grease.  The  odor  of  the  flowers  is  absorbed  by 
the  grease,  the  flowers  being  replaced  by  fresh  ones  every 
morning  for  a  month,  when  the  grease,  or  "  pomade  "  as  it 
is  called,  is  collected  and  treated  with  alcohol  for  a  month. 
The  odor  leaves  the  grease  and  passes  to  the  alcohol, 
which  is  then  known  as  essence  of  orange  flowers. 

Dried  and  candied  peel.  —  Both  orange  and  lemon  peel 
are  in  good  demand,  both  candied  and  dried.  When  dried, 
the  peel  is  simply  removed  from  the  pulp,  cut  into  thin 
shreds,  and  dried  in  the  sun.  When  candied,  the  process 
is  very  similar  to  that  used  for  citron,  and  the  orange  and 
lemon  peels  are  not  shredded,  but  left  in  halves. 

Lime  juice.  —  Large  quantities  of  limes  are  grown  on  the 


340  Citrws  Fruits- 

islands  of  the  West  Indies.  The  green  Hmes  are  harvested 
and  shipped  to  market  in  barrels,  turning  yellow  on  the  way. 
The  ripe  fruit  which  falls  to  the  ground  is  gathered  up  and 
converted  into  several  different  by-products,  such  as  citric 
acid,  lime  oil,  and  lime  juice.  In  making  raw  lime  juice 
which  is  to  be  used  as  a  beverage,  only  clean,  sound  fruit 
is  used.  The  juice  is  expressed  by  passing  the  fruit  be- 
tween heavy  granite  rollers.  The  juice  is  allowed  to  stand 
until  the  mucilage  or  albuminous  matter  is  thrown  down, 
after  wdiich  it  is  filtered  and  bottled.  If  the  fruit  used 
is  clean  and  sound,  the  raw  juice  should  keep  without 
any  preservative  being  added.  Lime  juice  cordial  is  made 
by  mixing  the  raw  juice  with  various  brandies  and  other 
ingredients. 

Orange  paste.  —  A  large  amount  of  orange  paste  is  used 
by  confectioners.  It  is  made  by  grinding  and  macerating 
fresh  orange  peels,  and  after  the  addition  of  an  equal 
weight  of  sugar  evaporating  down  into  hard  cakes  which 
are  broken  up  and  packed  in  wooden  buckets.  This  or- 
ange paste  is  one  of  the  few  citrus  by-products  which  is 
already  being  manufactured  in  California. 

Crysiallized  baby  oranges.  —  The  small  green  oranges 
which  drop  from  the  trees  during  June  and  known  as  the 
"June  drop  "  may  be  gathered  and  made  into  a  pleasing 
confection  known  as  crystallized  baby  oranges.  Fruits 
between  one-half  and  one  inch  in  diameter  are  best  and 
should  be  gathered  frequently  and  not  allowed  to  wilt  on 
the  ground.  The  fruits  are  placed  in  brine,  gradually  in- 
creasing the  strength  until  fermentation  is  prevented. 
They  may  remain  in  brine  indefinitely,  provided  the  brine 
is  changed  occasionally.     When  ready  for  processing,  the 


By-Produch-  341 

fruits  are  boiled  in  several  chaii<;;es  of  fr(>sh  water  until 
free  from  salt,  and  tender,  after  which  a  hot  weak  sugar 
sirup  is  poured  over  them.  This  solution  is  replaced  by 
one  more  dense  each  day  until  the  fruits  will  take  up  no 
more  sugar.  They  are  then  dried  and  dipped  in  a  very 
thick  sugar  solution  and  allowed  to  cool  slowly  when  the 
sugar  will  crystallize  out  over  the  surface.  The  fruit  is 
now  ready  for  packing. 

Glaced  kum.quats.  —  Chinese  and  Japanese  prepare  a 
quantity  of  glaced  kimiquats,  a  certain  amount  of  which 
is  shipped  into  this  country.  The  fruits  are  jiicked  when 
ripe  and  several  slits  made  in  the  sides.  Sometimes  the 
seeds  are  squeezed  out  through  the  slits,  sometimes  not. 
The  fruit  is  boiled  until  tender  and  then  carried  gradually 
through  a  series  of  sugar  solutions  of  increasing  density 
until  they  will  take  up  no  more.  They  are  then  dried  and 
dipped  in  a  very  heavy  hot  sirup  and  quickly  dried.  In- 
stead of  crystallizing  the  sugar  will  glace  over  the  surface. 


DOMESTIC    RECIPES 

In  addition  to  the  foregoing  there  are  a  large  number  of 
pleasing  preserves,  marmalades,  and  other  preparations 
which  may  be  made  to  advantage  in  the  home  kitchen. 
Some  of  these,  such  as  Dundee  marmalade,  are  manu- 
factured in  quantity  and  shipped  to  distant  markets. 
While  it  is  deemed  inathisable  to  give  a  very  large  num- 
ber of  home  receipts,  still  a  few  of  the  more  im])()rtant 
ones  may  prove  of  interest  and  value. 

Orange  or  lemon  jelly.  —  Slice  fruit  thinly,  rind  and  all, 
place  in  double  boiler  with  cover,  and  boil  slowly  for  20 


342  Citrus  Fruits 

minutes  without  stirring.  Press  out  juice  and  filter 
through  several  thicknesses  of  muslin.  Add  a  little  more 
than  an  equal  volume  of  sugar.  Boil  on  slow  fire  three 
minutes  and  pour  into  jelly  glasses  while  hot.  In  some 
cases  a  small  amount  of  gelatine  is  added  before  boiling, 
but  if  properly  made  as  above  directed  this  should  not  be 
necessary. 

Orange  marmalade.  —  Large  amounts  of  orange  marma- 
lade are  made  in  Dundee,  Scotland,  from  whence  it  is 
shipped  to  all  parts  of  the  world.  The  oranges  used  in  the 
manufacture  of  this  marmalade  are  the  bitter  oranges 
grown  in  the  district  of  Valencia  in  Spain  and  shipped  to 
Scotland  after  being  shredded  and  canned.  Most  of  the 
marmalade  made  in  California  is  made  from  sweet  oranges 
and  pomelos.  A  little  of  the  characteristic  flavor  of  the 
bitter  orange  may  easily  be  secured  by  replacing  a  few  of 
the  sweet  oranges  with  bitter  ones. 

Slice  one  dozen  oranges  thin,  throwing  away  ends,  and 
one-half  dozen  lemons,  removing  all  seeds.  Measure 
the  fruit,  and  add  half  as  much  water.  Let  stand  over 
night.  Next  morning  boil  the  fruit  in  the  same  water 
until  tender.  Remove  from  fire  and  weigh  and  to  each 
pound  of  fruit  and  licpiid  add  one  pound  of  sugar.  Boil 
until  it  jellies,  which  should  require  about  twenty  minutes. 
Do  not  have  the  fruit  too  ripe  ;  it  should  be  fresh  and  firm. 

Pomelo  marmalade.  —  Slice  one  pomelo,  one  orange,  and 
one  lemon,  rejecting  seeds  and  core.  Measure  the  fruit 
and  add  to  it  twice  the  quantity  of  water.  Let  stand  in 
an  earthen  dish  over  night  and  next  day  boil  slowly  until 
peel  is  tender.  Let  stand  another  night  and  the  second 
morning  measure  and  add  an  equal  volume  of  sugar. 


By-Produds  343 

Place  in  covered  double  boiler  and  boil  slowly  for  a  half 
hour  or  until  it  jellies.  The  fruit  should  not  be  stirred 
during  boiling. 

Citrus-rhubarb  inarnialade. — Take  six  pounds  of  fresh 
rhubarb,  four  large  oranges,  four  lemons,  and  one  large  cup 
finely  chopped  walnuts.  Cut  the  oranges  and  lemons  into 
thin  slices,  rejecting  ends  and  seeds.  Add  to  the  rhubarb, 
which  has  been  cut  into  small  pieces.  Put  four  large  cups 
of  sugar  over  this  and  let  stand  over  night.  Next  morning 
add  four  more  cups  of  sugar  and  boil  down.  Just  before 
placing  in  jars  and  while  still  hot  stir  in  the  chopped  wal- 
nuts. 


CHAPTER   XIX 
MARKETING 

The  different  methods  of  selling  California  citrus  fruits 
may  be  grouped  for  convenience  under  four  general  heads, 
which,  with  the  proportion  of  fruit  now  (1913-14)  sold  by 
each  method,  are  approximately  as  follows  : 

13  %  ^liscellaneous  sales. 
5%  Sales  by  independent  growers  who  ship  to  market. 

20  %  Independent  association  sales. 

62%  Sales  through  the  California  Fruit  Growers'  Ex- 
change. 

Under  the  head  of  miscellaneous  local  sales,  fruit  is  dis- 
posed of  in  various  ways.  It  may  be  sold  either  for  a  lump 
sum  on  the  trees  to  itinerant  packers  and  speculators,  or  it 
may  be  contracted  for  by  hotel  syndicates  to  be  delivered 
as  needed.  The  management  of  the  dining  cars  and  eating 
houses  of  a  large  railroad  company,  for  example,  often  se- 
lects certain  crops  of  oranges  which  are  bought  for  a  stated 
price  per  pound,  to  be  picked  and  delivered  as  needed. 
Commission  men  wull  sometimes  secure  a  contract  for  a 
certain  amount  of  fruit  of  a  certain  grade  to  be  delivered 
in  the  East  or  in  Australia  or  Hongkong,  and  then  send  an 
agent  around  the  country  buying  the  fruit  wherever  it 
can  be  secured.  Such  buyers  will  usually  contract  with 
344 


Marketing  345 

some  indepeiulent  local  packing-house  tor  the  packing  of 
the  fruit. 

Under  the  head  of  iude})endent  grower-shippers  are  in- 
cluded certain  large  growers  who  have  sufficient  acreage 
to  warrant  a  packing-house  of  their  own.  In  most  cases 
such  shippers  have  old  and  especially  favorable  connec- 
tions in  certain  markets  where  their  reputation  is  high  and 
their  old  customers  secure.  Independent  shippers  usually 
have  some  special  or  unique  advantage  which  relieves 
them,  to  an  extent,  from  the  common  vicissitudes  of  the 
market.  The  chief  stockholder  in  a  large  hotel  in  Chicago 
or  Boston,  for  instance,  who  owns  a  winter  home  in  an 
orange  grove  in  California,  will  naturally  ship  his  fruit  to 
his  own  hotel  for  consumption. 

Independent  associations  are  groups  of  small  growers 
who  have  united  together  in  building  a  cooperative  pack- 
ing-house, yet  who  for  some  reason  have  not  afliliated  with 
the  Exchange,  but  sell  their  fruit  through  commission  men 
in  the  various  markets.  ]\Iany  of  these  associations  who 
think  they  are  doing  a  little  better  outside  the  Exchange 
would  quickly  join  and  support  the  Exchange  should  it 
ever  appear  in  danger  of  failure  through  lack  of  sui)i)ort. 
They  prefer  for  the  present,  perhaps,  to  sail  in  the  calm 
water  close  under  the  lee  of  the  Exchange. 


THE    CALIFORNIA    FRUIT    GROWERS     EXCHANGE 

This  great  cooperative  organization  of  growers  is  the 
child  of  necessity.  The  season  of  1892-93  was  particu- 
larly disastrous  as  far  as  turning  fruit  into  money  was 
concerned,  and  the  market  conditions  and  arrogance  of 


346  Citrus  Fruits 

the  railroads  were  intolerable.  Accordingly  the  Southern 
California  Fruit  Exchange  was  organized  in  Los  Angeles 
on  October  2,  1895,  in  order  to  provide  certain  marketing 
of  the  fruit  by  more  uniform  methods.  Ten  years  later  the 
name  of  the  organization  was  changed  to  the  present  title. 

The  California  Fruit  Growers'  Exchange  has  its  home 
office  in  the  Consolidated  Realty  Building  in  Los  Angeles. 
Its  organization  is  tersely  described  by  G.  H.  Powell,  the 
General  Manager,^  as  follows  : 

"The  California  Fruit  Growers'  Exchange  is  an  organi- 
zation which  acts  as  a  clearing  house  in  providing  the 
facilities  through  which  6500  growers  distribute  and  mar- 
ket their  fruit.  There  are  three  foundation  stones  in  the 
exchange  system  —  the  local  associations  of  growers,  the 
district  exchanges,  and  the  central  exchange.  The  local 
associations,  the  district  exchanges,  and  the  central  or 
California  Fruit  Growers'  Exchange  are  organized  and 
managed  by  the  growers  on  a  non-profit  cooperative 
basis,  each  of  them  operating  at  cost,  and  each  distribut- 
ing the  entire  net  proceeds  to  the  growers  after  operat- 
ing expenses  are  deducted." 

The  local  exchange.  —  "The  California  Fruit  Growers' 
Exchange  comprises  115  local  associations,  each  of  which 
has  from  40  to  200  members.  The  growers  usually  organ- 
ize as  a  corporation  without  profit,  under  the  laws  of  Cali- 
fornia, issuing  stock  to  each  member  in  proportion  to  his 
bearing  acreage,  to  the  number  of  boxes  he  ships,  or  in 
equal  amounts  to  each  grower.  The  association  assembles 
the  fruit  in  a  packing-house,  and  there  grades,  pools,  packs, 
and  prepares  it  for  shipment.     The  associations  are  man- 

1  California  Cultivator,   March  13,  1913. 


Marketing  347 

aged  by  a  board  of  directors  through  a  manager  and  are 
conducted  exclusively  for  the  benefit  of  the  growers. 
They  declare  no  dividends  and  accumulate  no  ])r()fits. 
The  fruit  is  pooled  each  month,  or  for  a  shorter  period,  each 
grower  receiving  his  proportion  of  the  proceeds  received 
for  each  grade  shipped  during  the  pool.  ]\Iany  of  the 
associations  pick  the  fruit,  and  some  of  them  j)rune  and 
fumigate  the  trees  for  the  members.  Each  association 
has  brands  for  each  grade,  and  when  a  carload  is  ready 
for  shipment  it  is  marketed  through  the  district  exchange, 
of  which  the  association  is  a  member,  througli  the  agents 
and  facilities  provided  by  the  California  Fruit  Growers' 
Exchange." 

The  district  exchange.  —  "There  are  seventeen  district 
exchanges.  These  exchanges  are  corporations  without 
profit.  There  may  be  one  or  more  district  exchanges  in  a 
community,  depending  upon  the  number  of  local  associa- 
tions and  other  local  conditions.  The  district  exchange 
acts  as  a  clearing  house  in  marketing  the  fruit  for  the  asso- 
ciations through  the  California  Fruit  Growers'  Exchange 
and  acts  as  a  medium  through  which  most  of  the  business 
relations  between  the  exchange  and  the  local  associations 
are  handled.  The  district  exchange  orders  cars  and  sees 
that  they  are  placed  by  the  railroad  at  the  various  associa- 
tion packing-houses ;  keeps  record  of  the  cars  shipped  by 
each  association,  with  their  destinations;  informs  itself, 
through  the  California  P^'ruit  Growers'  Exchange,  of  all 
phases  of  the  citrus  marketing  business ;  places  the  in- 
formation before  the  associations  ;  receives  the  returns  for 
the  fruit  through  the  central  exchange,  and  returns  the 
proceeds  to  the  associations." 


348  Citrus  Fruits 

The  central  c.rrhnugr.  -  "Tli(>  California  Fruit  Growers' 
Exchange  is  a  non-j)rofit  (•()ri)oration  under  the  laws  of 
California.  It  is  formed  hy  17  district  exchanges,  with  a 
paid-in  capital  stock  of  $17(K)-.  It  is  managed  by  a  Board 
of  17  directors  through  a  general  manager,  one  director 
representing  each,  district  exchange.  The  function  of  the 
California  Fruit  Growers'  Exchange  is  to  furnish  market- 
ing facilities  for  the  district  exchanges  at  a  pro-rata  share 
of  the  cost.  The  exchange  places  bonded  agents  in  the 
principal  markets  of  the  United  States  and  Canada,  defines 
the  duties  of  the  agents,  and  exercises  supervision  over 
them.  It  gathers  information  through  them  of  conditions 
in  each  market,  receives  telegraphic  advices  of  the  sale 
of  each  oar,  and  furnishes  the  information  every  day  in 
bulletin  form  to  the  local  associations.  The  exchange 
business  is  on  a  cash  basis ;  it  makes  prompt  accounting 
of  returns  to  the  growers  through  the  district  exchanges; 
takes  care  of  litigation  that  arises  in  connection  w^ith 
the  marketing  of  the  fruit ;  handles  all  claims  ;  conducts 
an  extensive  advertising  campaign  to  increase  the  demand 
for  citrus  fruit ;  develops  new  markets  and  performs  such 
other  functions  as  are  set  forth  in  the  contract  between 
the  central  exchange  and  the  district  exchanges.  The 
central  exchange  levies  an  assessment  against  each  district 
exchange  for  a  pro-rata  share  of  the  expense  on  the  basis 
of  the  number  of  boxes  shipped.  It  declares  no  dividends. 
It  does  not  buy  or  sell  fruit  or  any  other  commodity,  and 
exercises  no  control  either  directly  or  indirectly  over  sale 
or  purchase.  Its  function  is  to  provide  facilities  for  the 
distribution  and  marketing  of  the  fruit  for  those  shippers 
who  desire  such  facilities.     Under  the  exchange  system 


Marketing  :U9 

every  shipper  reserves  the  right  to  regulate  and  control  his 
own  shipments ;  to  develop  his  own  brands  of  fruit ;  to 
use  his  own  judgment  as  to  when  and  in  what  amount  it 
shall  be  shipped,  and  the  price  he  is  willing  to  receive, 
reserving  the  right  of  free  competition  with  all  other 
shippers,  including  the  members  of  the  same  organization, 
uncontrolled  by  any  one.  The  agent  in  the  market  acts 
directly  under  the  order  of  the  shipper,  who  determines 
the  prices  at  which  each  car  shall  be  sold  outside  of  the 
auction  markets,  and  all  other  matters  connected  with  its 
distribution,  the  California  Fruit  Growers'  Exchange 
acting  as  the  medium  through  which  orders  pass  from  the 
agent  to  the  shipper,  but  never  selling  a  car  or  determining 
the  price  at  which  the  fruit  shall  be  sold. 

"The  exchange  is  a  democratic  organization;  the 
growers  exercise  control  over  all  matters.  JMembership 
in  the  exchange  is  voluntary  ;  a  grower  may  witliflraw 
from  an  association  at  the  end  of  a  year ;  an  association 
may  withdraw  from  a  district  exchange,  and  a  district  ex- 
change may  withdraw  from  the  central  exchange,  —  these 
relations  being  set  forth  in  the  various  contracts  that  hold 
the  members  together.  There  is  no  attempt  on  the  part 
of  the  central  exchange  to  regulate  shipments,  to  eliminate 
competition,  divide  the  territory  or  business,  or  to  influ- 
ence prices.  In  this  connection  its  functions  are  to  keep  the 
associations  informed  daily  regarding  the  shipments  from 
the  state ;  the  general  movement  of  exchange  cars,  the 
general  conditions  of  the  different  marketing  points ;  the 
prices  at  which  the  exchange  fruit  is  sold  ;  and  in  furnish- 
ing such  other  information  as  will  allow  the  growers  and 
shippers  through  their  association  and  district  exchanges  to 


350  Citrus  Fruits 

decide  the  questions  of  distribution  and  marketing  for 
themselves. 

"  One  third  of  the  entire  shipments  are  sold  at  public 
auction,  the  remainder  through  unrestricted  private  com- 
petition. There  is  no  uniformity  in  price  in  the  different 
brands,  because  the  fruit  in  each  section,  on  account  of 
the  soil  and  other  local  conditions,  has  an  individuality, 
of  its  own,  and  every  brand  sells  on  its  own  merits. 

"The  exchange  is  organized  into  several  divisions; 
sales,  legal,  traffic,  advertising,  insurance,  and  mutual 
protection,  and  a  supply  department  which  furnishes  the 
materials  used  in  the  packing-houses  and  on  the  ranches, 
at  cost  to  the  members.  The  exchange  does  not  consign 
fruit.  It  is  shipped  on  order  ;  sold  f .  o.  b. ;  or  sold  '  de- 
livered, subject  to  usual  terms.'  The  exchange  maintains 
district  managers  in  all  of  the  important  cities  of  the 
United  States  and  Canada.  These  employees  are  exclu- 
sively salaried  agents,  engaged  only  in  the  sale  of  fruit, 
in  the  development  of  markets,  and  in  handling  the  local 
business  problems  of  the  exchange." 

The  money  received  by  the  selling  agents  for  fruit  is 
deposited  by  them  in  national  banks  to  the  credit  of  the 
central  exchange,  which  forwards  it  to  the  district  exchange 
and  is  by  them  distributed  to  the  growers.  The  exchange 
has  collected  more  than  one  hundred  and  thirty-nine 
millions  of  dollars  in  addition  to  freight  charges  for  citrus 
fruits  in  the  last  ten  years,  and  the  losses  from  bad  debts 
to  date  have  been  less  than  seven  thousand  dollars.  The 
exchange  returns  (f.  o.  b.  California)  for  fruit  shipped 
in  the  season  1913-14  were  about  eighteen  million  dollars. 

The   exchange   carries   on   two   forms   of    advertising. 


Marketing  351 

Space  in  daily  newspapers  in  all  important  cities  is  bought 
to  the  extent  of  .S2()0,()(M)  or  more  a  year.  In  order  to 
secure  the  chief  benefits  of  this  advertising  for  the  members 
of  the  exchange,  who  pay  for  it,  there  has  been  devised  a 
special  quality  brand  known  as  "  Sunkist  "  (see  Fig.  112), 
the  copyright  for  which  is  owned  by  the  exchange.  This 
brand  is  used  by  all  exchange  associations  as  an  addi- 
tional sticker  placed  on  their  best  brands  only.  The 
tissue  paper  wrappers  used  on  fruit  under  this  brand  bear 
the  "sunkist"  emblem  and  such  wrappers  are  redeemable 
in  part  payment  for  table  silverware.  This  ware  is  triple 
plated  and  of  good  quality  and  bears  a  special  orange 
design.  In  1912,  1,750,()()()  pieces  of  silverware  were  dis- 
tributed in  return  for  orange  and  lemon  wrappers,  and  the 
exchange  has  become  the  largest  single  buyer  of  this  class 
of  silverware  in  the  world.  In  the  Chicago  office,  forty 
mailing  clerks  are  required  to  take  care  of  this  business. 

The  expense  of  maintaining  the  exchange,  including 
advertising  and  every  other  expense,  has  never  been  as  high 
as  3  per  cent  of  gross  sales,  while  ordinary  commission  and 
brokerage  charges  of  other  agencies  vary  from  5  to  10  per 
cent  for  selHng  alone.  In  1914  the  total  cost  of  selling, 
including  advertising  and  the  maintenance  of  the  sub- 
exchanges,  amounted  to  Of^oV  c^^nts  a  box. 

It  is  not  a  difficult  matter  to  organize  an  association. 
The  money  required  for  incidental  and  organization  ex- 
penses will  be  supplied  by  the  membership  fees  of  five  or 
ten  dollars.  The  money  required  for  buikling  the  packing- 
house and  beginning  work  is  usually  borrowed  from  the 
banks  on  association  notes  personally  indorsed  by  the 
directors.     When  the  sale  of  fruit  begins  a  small  amount 


352  Citrus  Fruits 

to  the  box  is  held  back  with  which  to  gradually  pay  off 
the  notes.  When  real  propert>',  such  as  a  packing-house 
and  site,  is  acquired  it  may  be  mortgaged  for  as  much  as 
possible  in  order  to  relieve  the  directors  of  personal  liabil- 
ity on  the  first  notes  issued.  The  membership  fee  should 
be  kept  low  in  order  that  new  members  may  join  at  any 
time  as  old  members  drop  out  for  one  reason  or  another. 
Most  associations  desire  as  large  a  membership  as  possible, 
as  it  is  more  economical  to  pack  fruit  in  large  quantities 
and  in  a  large,  well-equipped  house. 

Every  association  should  act  squarely  and  honestly  with 
its  customers.  Special  markets  should  be  developed  and 
fruit  of  uniformly  good  grade  shipped  regularly  to  those 
markets  regardless  of  fluctuation  in  prices.  It  is  usually  poor 
policy  to  chase  high  prices  by  changing  quickly  from  one 
market  to  another.  It  should  be  the  ambition  of  each  as- 
sociation to  develop  a  high  reputation  for  its  brands  of 
fruit  on  certain  markets  and  then  stay  by  those  markets 
through  the  season,  always  striving  to  give  good  values  and 
please  the  okl  customers. 

"  The  distribution  of  the  oranges  and  lemons  of  each 
grower  must  be  uniform  throughout  the  year  on  a  mer- 
chandizing basis ;  neither  the  grower  nor  shipper  can  af- 
ford to  speculate  on  the  market.  The  fruit  should  go 
forward  naturally  from  each  grove  during  the  period  when 
it  possesses  the  best  quality  for  that  district.  Regular 
distribution  increases  consumption  ;  stabilizes  the  business 
of  the  shipper,  the  jobber,  and  the  retailer.  It  furnishes 
the  consumer  a  supply  at  the  lowest  average  return  be- 
cause the  product  is  handled  by  every  one  at  a  reasonable 
distributing  profit.     The  distributing  cost  of  citrus  fruit 


Marketing  353 

after  it  reaches  the  jobber,  like  many  other  food  products, 
represents  approximately  45  per  cent  of  the  consumer's 
cost.  Erratic,  speculative  distribution  increases  the  dis- 
tributing costs ;  it  results  in  a  lower  price  to  the  producer 
and  a  higher  cost  to  the  consumer."  ' 

Some  years  ago  the  citrus  growers  of  Florida  sent  a 
committee  to  California  to  study  the  methods  of  the  Cali- 
fornia Exchange.  As  a  result  of  this  the  Florida  Citrus 
Exchange  was  organized  in  the  fall  of  1909,  and  is  now  a 
successful  organization.  About  22  per  cent  of  the  Florida 
Crop  of  1913-14  was  handled  through  the  Exchange. 

Citrus  Protective  League  of  California 

This  is  a  voluntary  organization  formed  in  jNIarch,  1906, 
by  representatives  of  growers,  shippers,  and  shipping  or- 
ganizations in  nearly  all  of  the  citrus  growing  localities 
of  the  state  to  handle  the  public  policy  questions  that 
affect  the  industry  as  a  whole.  Its  purpose  is  to  represent 
the  grower  and  shipper  in  handling  such  questions  as : 
railroad  rates  and  transportation  problems ;  customs 
tariffs  and  other  governmental  relations ;  state  and 
federal  legislation  that  applies  directly  to  the  business,  and 
all  other  questions  of  a  general  nature  that  affect  the  up- 
building of  the  industry,  except  the  marketing  of  fruit. 

The  League  is  directed  by  an  Executive  Committee  of 
nine  and  by  a  secretary  and  manager,  the  Executive  Com- 
mittee having  been  appointed  by  an  Administrative  Com- 
mittee of  thirty  of  the  principal  growers  and'  shippers 

1  Report  of  G.  H.  Powell,  General  Manager,   Calif ornin  Fruit 
Growers'  Exchange,  1914. 
2a 


354  Ciirm  Fruits 

who  act  as  a  governing  committee,  and  who  were  selected 
from  the  representative  delegates  who  organized  the 
League  in  1906.  The  League  represents  about  90  per  cent 
of  the  growers  and  shippers  of  the  state,  and  is  supported 
by  funds  raised  by  general  assessment  based  on  the  num- 
ber of  cars  of  fruit  shipped  by  each  member  during  the 
preceding  year. 

In  conclusion  it  may  be  well  to  point  out  that  during  the 
last  decade  the  citrus  fruit  acreage  in  California  has  more 
than  doubled.  From  1900  to  1914  the  size  of  the  crop 
increased  254  per  cent.  Li  order  that  consumption  may 
keep  pace  with  this  rapid  increase  in  production,  it  is 
extremely  important  that  the  growers  loyally  support  the 
organizations  which  are  developing  a  comprehensive, 
economical,  and  efficient  system  for  distributing,  selling, 
and  advertising  citrus  fruits. 

It  is  also  highly  important  that  a  profitable  by-product 
industry  be  established.  A  means  of  disposing  of  low- 
grade  fruit  at  home  will  do  more  than  anything  else  toward 
keeping  such  fruit  from  glutting  the  markets  and  depress- 
ing the  prices  of  fancy  fruit.  This  is  bound  to  result  in 
an  improvement  in  the  grades  of  fruit  shipped  to  market, 
with  consequent  marked  increase  in  consumption. 


CHAPTER   XX 

PROFIT  AND  LOSS 

If  the  question  is  asked,  "  Does  citrus  culture  rccally 
pay?"  we  are  compelled  to  answer  "Yes  and  no."  It 
pays  handsomely  where  proper  conditions  are  combined 
with  knowledge,  industry,  common  business  sense,  and 
capital.  It  does  not  pay  in  many  cases  where  these  things 
are  not  combined.  Some  persons  make  very  large,  almost 
fabulous,  profits  growing  citrus  fruits,  and  these  examples 
are  widely  quoted  by  real  estate  agents  and  land  boomers. 
Other  persons  lose  money  consistently  year  after  year. 
When  we  consider  the  total  production  of  any  crop  in  the 
United  States,  such  as  corn,  wheat,  or  cotton,  we  find  the 
average  yield  an  acre  is  surprisingly  low.  Citrus  fruits 
are  no  exception  to  the  rule.  The  Citrus  Protective  League 
has  collected  a  great  deal  of  data  on  the  cost  of  production 
of  citrus  fruits,  and  Victor  Xewland,  a  student  at  the  Uni- 
versity of  California,  has  worked  out  the  average  prices 
received.  Such  large  collections  of  figures  should  not  be 
taken  too  seriously,  yet  they  possess  considerable  indica- 
tive value.  It  appears  that  the  average  l)ox  of  oranges 
for  the  five  years  preceding  1913  returned  a  net  profit  of 
15  cents  to  the  grower,  while  the  average  box  of  lemons 
produced  during  the  same  period  returned  a  loss  of  about 
355 


356  Citrus  Fruits 

20  cents.  And  yet  skillful  growers  have  commonly  made 
much  higher  profits  on  lemons  than  on  oranges,  and  a  good 
bearing  lemon  grove  will  sell  for  more  money  to-day  than 
an  orange  grove  of  similar  age.  This  means  that  there 
have  been  a  larger  proportion  of  failures  with  lemons  than 
with  oranges. 

There  are,  of  course,  many  reasons  why  some  citrus  trees 
fail  to  pay.  Some  trees  are  planted  with  the  object  of 
producing  fruit;  while  others,  w^e  regret  to  have  to  say, 
have  been  planted  for  the  purpose  of  making  it  easier  to 
sell  the  land.  There  is  a  great  deal  of  land  that  will  grow 
a  beautiful  young  tree  for  a  few  years,  but  upon  which 
bearing  trees  will  soon  fail.  A  considerable  acreage  of 
either  very  questionable  or  impossible  citrus  land  has  been 
planted  out  in  large  blocks  and  then  divided  up  and  sold 
to  unwary  investors,  who  in  most  cases  are  inexperienced 
persons  newly  arrived  from  other  parts  of  the  country. 
Much  citrus  acreage  is  sold  by  mail  to  absent  buyers,  a  very 
bad  practice.  It  is  strange  how  many  unsophisticated 
persons  there  are  in  Northern  cities  who  will  trustingly 
send  their  money  by  mail  to  some  agent  with  the  request 
that  he  "Be  sure  to  select  a  nice  orange  grove  for  them." 
Where  there  is  such  an  absolute  lack  of  business  sense  as 
this,  it  is  not  surprising  that  there  are  so  many  failures. 

Absentee  ownership  is  one  of  the  banes  of  the  citrus 
business.  If  a  person  cannot  visit  his  property  at  least 
once  a  month  and  look  after  the  various  operations  in  per- 
son, he  should  sell  out  to  some  one  who  can. 

Another  trouble  is  over-capitalization,  which  is  encour- 
aged by  speculation.  Many  beautiful  towns  and  cities 
have  been  built  hterally  in  the  orange  groves  and  the  in- 


Profit  and  Loss  357 

crease  in  value  of  the  land  for  residence  and  other  pur- 
poses has  increased  the  cai)ital  and  taxes  to  a  point  where  it 
becomes  difficult  to  make  any  but  the  most  expertly  man- 
aged citrus  orchards  pay. 

INIany  orchards  are  composed  largely  of  degenerate 
types  of  trees;  many  have  been  ruined  by  the  mottled- 
leaf  disease ;  and  many  are  too  frequently  visited  by  frost. 

Let  us  not  dwell  too  much  on  the  dark  side,  however,  but 
hasten  to  give  assurance  that  any  one  with  sufficient  capi- 
tal, a  reasonable  knowledge  of  horticultural  operations, 
and  ordinarily  good  business  judgment  may  easily  make 
a  good  profit  raising  citrus  fruits,  ])rovided  he  or  she  is 
careful  to  see  that  the  following  requirements  are  satisfied  : 

1.  A  location  in  a  proved  citrus  district,  reasonably 
free  from  frosts  and  winds  and  within  hauling  distance  of  a 
packing-house. 

2.  An  easily  worked,  fertile,  well-drained,  deep  soil, 
purchased  at  a  reasonable  price. 

3.  An  ample  supply  of  good  water. 

4.  Strong,  thrifty,  clean  trees  grown  from  carefully 
selected  buds  of  standard  \'arieties. 

5.  Proper  preparation  of  ground  and  planting  of  trees. 

6.  Personal  care  of  the  trees  with  conscientious  culti- 
vation, irrigation,  fertiUzation,  and  pruning. 

7.  The  exclusion  of  scale  insects  and  proi)er  treatment 
for  fungus  and  other  diseases. 

8.  Membership  in  a  local  cooperative  marketing  asso- 
ciation. 

These  may  be  called  the  eight  fundamental  require- 
ments for  success.  Failure  in  any  one  of  these  retiuire- 
ments  may  bring  about  the  failure  of  the  grove,  although 


358  Citrus  Fruits 

failure  does  not  necessarily  follow  in  every  case.  On  the 
other  hand,  if  each  of  these  requirements  is  fairly  met, 
success  is  as  sure  as  almost  any  horticultural  venture  can 
be.  In  addition  to  these  things  it  is  advisable  for  the  be- 
ginner to  cooperate  with  the  neighbors  toward  the  general 
good  of  the  district  by  joining  loyally  in  fumigating  and 
frost  fighting  campaigns.  The  College  of  Agriculture 
should  be  freely  consulted,  and  the  beginner  will  usually 
find  it  to  his  advantage  to  enroll  for  the  free  correspond- 
ence course  in  citrus  fruits  conducted  by  the  College. 

CAPITAL    REQUIRED 

The  next  question  to  be  considered  is,  "  How  much 
money  will  be  needed  to  meet  the  eight  requirements  for 
success  outlined  above  ? ' '  This  question  permits  of  no  defi- 
nite  answer  on  account  of  the  very  wide  variations  in  costs 
in  different  localities  and  under  different  conditions.  In 
some  locaUties  good  citrus  land  may  still  be  had  at  $150 
an  acre,  while  in  other  districts  it  may  be  considered  cheap 
at  $500  an  acre. 

Water  also  varies  very  w^idely  in  cost.  In  some  locali- 
ties where  there  is  comparatively  little  frost,  combined 
with  good  soil  and  other  natural  advantages,  the  cost  of 
water  has  soared  surprisingly  high.  After  the  local 
supply  has  all  been  appropriated,  additional  water  is 
often  brought  from  great  distances.  This  is  usually 
accomplished  by  forming  a  water  company  which  pur- 
chases sufficient  water  bearing  lands  and  installs  the 
necessary  pumping  plants,  tunnels,  and  aqueducts.  The 
necessary  amount  of    water  stock  in  such  a  company 


Profit  and  Loss  359 

(which  is  the  water  right)  sometimes  costs  as  much  as  $200 
an  acre  and  the  annual  assessments  for  pumping  expense 
and  repairs  may  be  as  much  as  $40  an  acre  a  year. 

The  following  estimate  gives  some  general  idea  of  the 
cost  of  bringing  a  young  grove  into  bearing  in  the  San 
Gabriel  ^^alley : 

Cost  of  Bringing  a  Ten  Acre  Orange  Orchard  to  Bearing 

10  acres  orange  land $1500 

Clearing  and  grading 2000 

Water  right 1500 

Trees,  1000  @  $1 1000 

Planting  trees  at  7^^  each 75 

Irrigating  system 200 

Irrigating  and  cultivating,  5  years        ....  2000 

Taxes  and  incidentals,  5  years 250 

Fertilizer,  3  years       .     .  ' 250 

Pruning        200 

Total  expense $8975 

Returns  from  fruit  less  packing  charge,  3  years  .     .     .       1200 

Total  investment  at  beginning  of  6th  year  .     .     .     $7775 

A  well  managed  orange  orchard  in  full  bearing  ought 
to  yield  250  packed  boxes  an  acre.  Many  orchards  aver- 
age much  more  than  this  amount.  The  cultural,  packing, 
and  selling  costs  ought  not  to  exceed  $2.00  a  box.  The 
average  selling  price  for  oranges  for  the  last  five  years  has 
been  about  $2.80. 

At  the  time  the  reduction  of  the  tariff  on  citrus  fruits  was 
under  discussion  in  Congress,  the  Citrus  Protective  League 
made  an  extensive  investigation  of  the  cost  of  producing 
oranges  and  lemons.  The  publications  of  the  League  con- 
tain some  very  extensive  tables  showing  all  items  of  cost 
in  great  detail,  from  which  the  following  figures  are  taken  : 


360  Citrm  Fruits 


Data  on  26,000  Acres  of  Oranges 

Average  cost  of  materials  an  acre        $83.24 

Average  cost  of  labor 52.82 

Average  cost  of  crop  an  acre $136.06 


Data  on  4,186,983  Boxes  of  Oranges 
Cost  per  Box 

Picking $.0771 

Hauling 0287 

Packing 3246 

Picking,  hauling,  and  packing $.4304 

Cultural  cost 8633 

Freight 828 

Refrigeration 0789 

Selling  and  collecting .07 

Total  cost  laid  down  in  market $2.2706 

Data  on  1,391,711  Boxes  of  Lemons 
Cost  per  Box 

Cost  of  growing $1,000 

Cost  of  picking 253 

Cost  of  hauling 039 

Cost  of  packing 596 

Cost  of  freight 840 

Cost  of  refrigeration 026 

Cost  of  seUing .070 

Total  cost  laid  down  in  market $2,824 

In  estimating  the  amount  of  capital  required  to  conduct 
a  bearing  citrus  orchard  for  a  year,  the  following  figures, 
also  taken  from  the  League  reports,  may  beiound  of  value. 
The  cost  of  superintendence,  administration,  and  depre- 
ciation are  omitted  : 


Profit  and  Loss 


361 


Cost  of  Operating  Bearing  Grove  an  Acre  a  Year  of    Oranges 


when 


Cultivating 

Pruning 

Irrigating 

Fumigating    (materials    and    labor) 

necessary     

Spraying  (when  necessary) 

Spreading  fertilizer 

Other  tree  care   (propping,  caring  for  sick 

trees,  etc.)        

Chemical  fertilizer        

Barn^-ard  manure  (when  used)       .     .     .     . 

Water 

Forage  and  grain  (feed  for  work  stock)    .     . 

Taxes 

Maintenance  and  repairs 

Incidentals 

Frost  protection  (when  used) 


$18.00 

$20.00 

S.OO 

22.50 

7.50 

12.00 

18.00 

20.00 

7.50 

7.50 

2.50 

2.50 

3.00 

5.00 

30.00 

35.00 

30.00 

30.00 

18.00 

20.00 

20.00 

20.00 

12.00 

10.00 

7.00 

7.00 

2.50 

2.50 

30.00 

40.00 

Tlie  above  columns  of  figures  are  not  added  for  the 
reason  that  no  orchard  requires  all  of  tliese  expenditures 
in  any  one  year.  The  same  orchard  would  not  be  fumi- 
gated and  sprayed,  and  manure  would  not  be  applied  e\ery 
year  as  sufficient  supplies  are  not  a\'ailable.  These  figures 
are  also  open  to  the  objection  that  they  represent  averages 
between  different  districts  and  hence  are  not  strictly  typi- 
cal of  any  one  district.  Inasmuch  as  they  are  susceptible 
to  such  wide  variations,  they  should  be  accepted  as  rough 
approximations  only.  See  also  statement  No.  1  on  pages 
162  and  163. 

The  Citrus  Protective  League  has  published  the  follow- 
ing figures  on  average  yields  including  all  varieties  of  or- 
anges and  lemons. 


362 


Citrus  Fruits 


Year 

Oranges  ave. 

26,000  Acres 

Boxes  per  Acre 

Lemons  ave. 

6137  Acres 

Boxes  per  Acre 

1906-7       

150.1 
129.5 
167.2 
136.7 
191.0 
157.6 

149.1 

1907-8       

187  1 

1908-9       

220.9 

1909-10     

196  1 

1910-11      

211.2 

Average  for  5  years 

196.2 

The  average  f.o.b.  price  received  for  oranges  for  the 
last  ten  years  is  about  $1.50  per  box  and  for  lemons  $2.00 
per  box. 


JUDGING    ORCHARDS    AND    LANDS 

It  is  poor  policy  to  examine  a  piece  of  prospective  land 
or  a  bearing  orchard  without  a  program.  This  is  espe- 
cially true  when  different  propositions  are  to  be  contrasted 
with  a  view  to  deciding  on  a  purchase.  Many  inexperi- 
enced people  buy  land  without  digging  into  it,  but  this 
practice  cannot  be  too  strongly  condemned.  In  arid 
countries  surface  indications  are  not  reliable  guides  as  to 
what  may  be  expected  below  the  surface.  Holes  should 
be  dug  at  least  six  or  seven  feet  deep  in  various  places  and 
the  soil  examined  for  changes  in  character,  hardpan, 
stone,  and  so  on. 

It  is  suggested  that  the  following  list  of  points  be  used 
in  going  over  every  piece  of  land.  Each  point  may  be 
weighted  after  the  fashion  of  a  score-card  and  thus  accurate 
comparisons  between  different  propositions  made  easier . 


Profit  and  Loss  363 

Score-card  for  Citrus  Land 

1.  Freedom  from  frost. 

2.  Water;  legal  right,  amount,  quality,  cost. 

3.  Kind  and  quality  of  soil.     Topography. 

4.  Continuity  of  tract  and  freedom  from  waste  land. 

5.  Freedom  from  stones  and  brush.     Cost  of  clearing 
and  grading. 

6.  Freedom  from  hardpan. 

7.  Freedom  from  alkali. 

8.  Drainage  outlet. 

9.  Susceptibility  to  wind. 

10.  Distance  from  scale  infested  orchard. 

11.  Nearness  to  town. 

12.  Nearness  to  packing-house  and  railroad  siding. 

13.  Quality  of  roads. 

14.  Price  per  acre. 

Additional  Points  for  Bearing  Groves 

15.  Uniformity  and  yield  record  of  trees. 

16.  Freedom  from  scale  insects. 

17.  Freedom  from  mottled-leaf  and  other  diseases. 

18.  Condition  of  trees  as  to  pruning  and  general  care. 

19.  Adaptability  of  variety  to  district. 


CHAPTER  XXI 

DISEASES  AND   THEIR  CONTROL 

Citrus  trees  are  susceptible  to  a  large  number  of  dis- 
eases, some  of  which  are  due  to  the  attacks  of  parasites 
and  some  to  physiological  derangements  of  nutrition. 
Practically  all  of  the  fungus  diseases  have  been  investi- 
gated by  scientists  and  are  fairly  well  understood,  while 
comparatively  little  progress  has  been  made  in  the  study 
of  physiological  diseases.  In  Florida  and  some  other 
humid  citrus  growing  regions  the  fungus  troubles  are  most 
common,  while  in  California  and  other  places  where  the 
climate  is  more  or  less  arid  the  fungus  troubles  are  less 
abundant  and  derangements  of  nutrition  due  to  unfavor- 
able soil  conditions,  alkali,  excessive  heat,  and  perhaps 
to  excessive  illumination  and  transpiration  are  very  fre- 
quently met  with. 

GUM    DISEASES 

Citrus  trees  are  apt  to  excrete  gum  from  a  number  of  differ- 
ent causes,  some  of  which  fall  in  each  of  the  classes  mentioned 
above. 

Brown  Rot  Gum-Disease 

Among  citrus  growers  this  trouble  is  usually  known  simply 
as  "gum-disease."     Until  recently  it  was  thought  to  be  due 
3G4 


Diseases  and  their  Control 


305 


solely  to  physiological  causes.  H.  S.  Fawcett  has  now 
shown  that  the  true  cause  is  none  other  than  that  old  enemy 
of  the  citrus  grower,  the  brown  rot  fungus  Piiihiaciintis 
citrophthora. 

Brown  rot  gumming 
is  most  common  on 
lemon  trees  and  is 
characterized  by  a 
copious  exudation  of 
gum  from  the  trunk 
just  above  the  bud 
union.  A  certain  area 
of  bark  surrounding 
the  gum  dies,  becomes 
hard  and  dry  with  no 
outer  evidence  of  fun- 
gus growth,  and  is 
often  pushed  slightly 
away  from  the  cam- 
bium by  the  pressure 
of  the  rapidly  forming 
gum.  This  kind  of 
gum-disease  may  be 
largely  prevented  by 
avoiding  the  soil  con- 
ditions most  favorable 
for  the  growth  of  this  soil-inhabiting  fungus.  No  water  should 
be  allowed  to  stand  in  contact  with  the  trunk.  Heavy  or 
adobe  soils  should  be  kept  well  worked  under  the  trees  and 
prevented  from  being  mounded  against  the  trunks.  It  will 
do  no  harm  to  draw  the  surface  soil  away  from  the  trunks, 
even  exposing  the  crown  roots,  provided  the  irrigation  water 
is   prevented   from    running   into    the    basin   thus   formed. 


Fig.  128.  — The  Fawcett  method  of  treat- 
ing gum-disease.    Note  types  of  scrapers. 


366  Citrus  Fruits 

The  fungus  gains  access  to  the  tree  either  through  abrasions 
of  the  l:)ark  or  directly  through  the  lenticels  or  breathing 
pores.  The  bark  of  the  sour  orange  is  very  resistant  to  in- 
fection and  trees  budded  six  or  more  inches  high  on  sour 
stock  are  quite  resistant. 

When  a  case  of  Ijrown  rot  gumming  is  discovered,  the  tree 
trunk  shoukl  be  treated  by  cutting  away  every  particle 
of  diseased  bark  and  painting  the  trunk  with  bordeaux 
mixture  paste,  made  as  follows  :  one  pound  of  bluestone 
and  two  pounds  of  unslaked  lime  with  water  to  make  a 
thick  whitewash.  It  is  advisable  on  all  heavy,  fungus  infested 
soils  to  apply  this  paste  as  a  preventive  to  all  healthy  trees 
so  situated  as  to  be  liable  to  gum-disease.  This  treatment 
shoulil  be  repeated  every  second  year  at  least. 

Botrytis  Gumming 

xA.nother  form  of  gum-disease  is  caused  by  the  fungus 
Botrytis  vulgaris  and  is  fairly  common  on  old  lemon  trees 
growing  on  low,  heavy  soils.  It  occurs  on  the  trunks  and 
is  characterized  by  a  much  less  copious  flow  of  gum  but  a  much 
more  general  infection.  The  outer  bark  becomes  soft  and 
dies  gradually  from  the  outside  inward,  differing  radically 
in  this  respect  from  the  brown  rot  gumming.  In  moist 
weather  the  disease  is  accompanied  by  cushions  of  small 
dark  gray  fruiting  bodies  scattered  over  the  surface  of  the 
dead  bark. 

The  proper  treatment  is  to  scrape  off  the  outer  dead  bark, 
leaving  the  inner  bark  wherever  it  is  alive,  and  applying  the 
bordeaux  paste.  Special  tools  have  been  developed  for 
scraping  and  they  shoidd  be  kept  in  the  bucket  of  paste  when 
not  in  use.  The  application  of  bordeaux  paste  to  healthy 
tree  trunks  is  suggested  as  a  good  preventive  for  this 
disease. 


Diseases  and  their  Control  367 


Scah/-bark 


The  sweet  orange  alone  is  subject  to  this  form  of  gumming 
which  occurs  in  patches  quite  generally'  over  the  trunk  and 
large  limbs  to  a  considerable  height.  In  this  case  the  outer 
bark  l)reaks  and  comes  away  in  small,  dry  scales,  lea\ing  the 
living  bark  underneath  with  a  rough  and  noduled  appearance 
and  with  a  large  number  of  small  gum  pockets  which  exude 
only  a  small  amount  of  gum.  .  In  severe  cases,  the  infected 
tree  or  branch  drops  its  leaves,  and  after  languishing  for  a  year 
or  two,  finally  dies.  In  some  cases,  large  vigorous  trees  may 
support  a  few  scaly-bark  patches  for  many  years  without 
any  serious  reduction  in  crop.  While  this  disease  has  been 
investigated  for  a  number  of  years,  the  cause  has  not  yet 
been  discovered,  and  no  satisfactory  treatment  is  known. 
Where  the  disease  occurs  only  on  the  branches,  they  should 
be  cut  off  below  the  diseased  area  and  burned.  Where 
the  disease  occurs  on  the  trunk,  it  is  advisable  to  scrape  the 
bark  thoroughly  and  apply  bordeaux  paste,  inasmuch  as  in 
certain  instances  this  has  appeared  to  be  of  some  value. 

Twig  Gumming 

Young  trees  and  nursery  stock  are  sometimes  affected  with 
gumming  of  the  twigs  which  is  apparently  caused  by  copious 
irrigation  when  the  soil  has  become  too  dry.  The  gum 
breaks  out  along  the  small  twigs  all  over  the  tree  with  splitting 
of  the  bark,  dropping  of  leaves,  and  dying  back  of  twigs. 
Vigorous  trees  always  recover  and  the  trouble  may  be  pre- 
vented by  giving  due  attention  to  regular  irrigation.  Some- 
times this  form  of  gumming  is  caused  by  a  period  of  desic- 
cating north  winfl.  Such  winds  do  not  affect  the  mature 
wood,  but  often  cause  the  bark  to  split  and  drops  of  gum 
form  on  vigorous  young  shoots. 


368 


Citrus  Fruits 


Leaf  Gamming 

This  is  very  common,  especially  on  orange  trees,  in  hot 
localities.  Dark  reddish  colored,  slightly  raised  spots  or 
areas  appear  on  the  leaves  in  places  where  they  have  been 
turned  up  and  the  under  side  exposed  to  the  sun  or  frost. 
These  spots  are  formed  by  the  secretion  of  a  gum-like  sub- 
stance in  the  tissue  just  under  the  epidermis  and  are  simply  the 
result  of  sunburn  or  frost  injury  at  a  time  when  the  leaves  are 
young  and  tender.  The  trouble  is  not  serious  and  need  not 
be  feared. 


Fig.  129.  —  Reddish  gum  areas  on  under  side  of  leaf  caused  by  sunburn. 


Gumming  of  Seed  Bed  Stock  (Pijthiacystis  citrophthora) 

It  often  happens  that  the  brown  rottungus,  becoming 
established  in  the  soil  used  for  seed  beds,  will  infect  large 
numbers  of  sweet  orange  seedlings,  especially  where  the  soil 
is  allowed  to  become  too  wet.  Many  of  the  seedlings  are 
girdled  at  the  surface  of  the  ground  and  entirely  ruined  and 
have  to  be  discarded  when  the  plants  are  dug  for  sale.  Sour 
orange  plants  are  somewhat  more  resistant,  but  even  they 
will  sometimes  show  a  considerable  amount  of  gumming, 
as  immunity  to  the  brown  rot  fungus  is  not  fully  acquired 
until  after  the  plants  have  been  transferred  to  the  nursery  row. 


Diseases  and  their  Control  309 

In  order  to  prevent  this  troul)le,  the  surface  soil  should  he 
kept  as  dry  as  the  health  of  the  plants  will  permit.  When 
the  first  indication  of  disease  is  noticed,  the  beds  should  he 
thoroughly  sprayed  with  bordeaux  mixture,  applying  the 
liquid  in  quantities  sufficient  to  drip  down  and  moisten  the 
entire  surface  of  the  soil. 

Exanthema  or  Die-hack 

This  disease  was  first  described  as  occurring  in  Florida  in 
1875  and  has  since  assumed  great  economic  importance, 
having  appeared  in  every  citrus  growing  district  in  that 
state.  The  annual  losses  directly  attributable  to  exanthema 
are  very  heavy. 

In  California  and  Arizona,  however,  the  losses  sustained 
from  the  eflfects  of  this  disease  have  been  comparatively 
light.  It  has  been  reported  from  several  localities  in  southern 
California,  but  in  very  few  cases  has  the  outbreak  been 
widespread  or  sufficiently  severe  to  attract  very  much  atten- 
tion. 

There  is  a  widespread  misunderstanding  in  regard  to  the 
term  "die-back."  There  is  of  course  a  dying  back  of  the 
branches  due  to  any  one  of  a  very  large  number  of  causes, 
such  for  example  as  mottled-leaf,  cottony-mold  fungus,  frost, 
and  the  like.  Seemg  dead  twigs  in  their  trees,  many  persons 
are  apt  to  jump  to  the  conclusion  that  the  trouble  is  die-back, 
which  presents  itself  to  their  minds  as  a  vague  though  no 
less  terrible  malady,  the  symptoms  of  which  they  do  not 
clearly  understand.  The  term  "exanthema"  is  a  Greek 
word  meaning  an  eruption  or  pustule  which  was  given  to 
this  particular  disease  by  Swingle  and  Webber  in  1896  and 
is  much  to  be  preferred  to  "die-back."  There  is  only  one 
exanthema  but  there  may  be  many  kinds  of  die-back. 

Exanthema  has  more  symptoms  than  almost  any  other 
2b 


370 


Citru.s  Fruitfi 


plant  disease,  and  there  is  little  excuse  in  failing  on  a  diag- 
nosis. The  first  indication  of  exanthema  appears  as  an  ab- 
normally dark  green  color  of  the  leaves  near  the  center  of 
the  tree.  This  is  followed  by  a 
dying  back  of  the  young  growth 
with  the  formation  of  small 
swellings  or  gum  pockets  at  the 
nodes.  These  often  crack  open 
and  tears  of  gum  are  exuded 
from  the  very  young  twigs,  while 
the  cracks  on  larger  twigs  appear 
filled  with  a  red  or  brown 
gummy  substance.  Often  af- 
fected twigs  will  attempt  a  new 
growth  but  succeed  only  in  form- 
ing clusters  of  sickly,  pale 
colored  buds  in  the  axils  of  the 
leaves.  Water  sprouts  often 
arise  from  healthy  wood  below 
the  diseased  tissue,  which  in  turn 
may  or  may  not  become  affected. 
The  fruit  on  badly  affected 
branches  either  falls  or  remains 
small  and  pale  yellow  in  color. 
Usually  the  fruit  which  reaches 
some  size  exhibits  a  very  char- 
acteristic dark  brownish  red 
stain  which  appears  as  irregular 
patches  of  gummy  material  laid 
over  the  surface.  These  red  areas 
are  usually  slightly  elevated,  and  badly  affected  fruit  often 
splits  open  longitudinally  while  hanging  on  the  tree.  Affected 
fruit  is  usually  abnormally  thick  skinned,  contains  numerous 


Fig.  130. — Exanthema  pustules 
on  Valencia  orange  twigs. 


Diseases  and  their  Control  o71 

gum  pockets  at  the  center,  and  in  tlie  case  of  oranges  has  an 
insipid  sweet  taste.  In  many  cases  exanthema  is  accom- 
panied by  mottled-leaf,  although  this  is  prol)al)ly  merely  a 
coincidence,  as  there  is  no  known  connection  between  the  two 
diseases.  Exanthema  is  most  common  on  the  orange  al- 
though it  has  been  found  by  the  writer  on  both  lemon  and 
pomelo. 

From  all  its  appearances  exanthema  would  naturally  be 
supposed  to  be  a  fungus  disease,  but  this  appears  not  to  be  the 
case.  A  great  deal  of  scientific  investigation  has  been  ex- 
pended, but  as  yet  no  fungus  or  other  parasite  has  been  found 
connected  with  the  trouble.  Experiments  have  shown 
moreover  that  the  disease  can  be  produced  in  healthy  plants 
without  the  aid  of  any  parasite  whatever.  For  these  reasons 
it  is  considered  to  be  a  physiological  derangement  of  the 
vital  functions  caused  by  irregular  or  improper  food  and 
moisture  supply  ;  in  other  words,  a  form  of  plant  indigestion. 
Citrus  plants  appear  to  be  especially  susceptible  to  various 
forms  of  malnutrition. 

In  Florida  the  cause  of  this  condition  has  been  fairly  well 
established.  It  has  been  found  to  be  due  to  an  excess  of 
ammonia  in  the  soil  resulting  from  applications  of  stable 
manure  or  other  form  of  organic  nitrogen.  Florida  growers 
are  almost  certain  to  huxe  exanthema  if  they  apply  large 
amounts  of  dried  blood  or  cottonseed  meal,  or  i)lant  the  trees 
on  land  previously  occupied  by  cattle  pens  or  chicken  yards. 
By  being  scrupulously  careful  to  avoid  these  things  Florida 
growers  have  been  able  to  reduce  the  amount  of  exanthema 
to  a  minimum. 

In  California,  however,  the  conditions  are  very  dift'erent. 
Here  growers  apply  organic  manures  in  very  large  amounts 
with  apparent  impunity,  as  far  as  exanthema  is  concerned. 
Why  this  marked  difference  should  exist  is  certainly  a  mys- 


372  Citrus  Fruits 

tery,  but  it  exists  nevertheless.  The  chief  causes  of  exan- 
thema in  CaUfornia  are  improper  soil  drainage  and  faulty 
soil  structure  ;  or  as  Lipman  has  recently  suggested,  the  direct 
cause  may  be  an  abnormally  slow  nitrification  in  the  soil 
accompanied  by  abnormally  rapid  ammonification,  thus  forc- 
ing the  plants  to  take  up  ammonia  compounds. 

Exanthema  may  be  cured  entirely  by  the  removal  of  the 
conditions  causing  the  trouble.  Where  ground  water  is  the 
cause,  the  land  may  be  drained,  but  where  an  open  porous 
subsoil  allows  the  water  to  pass  down,  but  on  account  of  its 
open  nature  does  not  permit  the  return  of  the  water  by  capil- 
larity, the  remedy  is  very  difficult  or  impossible.  Such  lands 
should  not  be  planted  to  citrus  fruits. 

Mal-di-gomma  or  Foot-rot 

In  European  citrus  districts  as  well  as  in  Florida  foot-rot 
has  caused  heavy  losses.  In  California,  however,  it  is  com- 
paratively rare.  It  is  thought  to  be  caused  by  a  fungus 
of  some  kind  which  produces  rotting  of  the  roots  quite 
distinct  from  that  described  above.  The  decay  starts 
in  the  bark  of  the  main  roots,  which  becomes  soft  and 
slimy,  and  gradually  spreads  from  the  surface  of  the  ground 
downward.  This  is  accompanied  by  a  yellowing  and  drop- 
ping of  the  leaves  in  that  part  of  the  top  directly  over  the 
diseased  roots.  When  disturbed,  the  rotten  roots  have  a 
peculiar  and  offensive  odor. 

Lemon  roots  are  quite  susceptible,  sweet  orange  somewhat 
less  so,  while  sour  orange  is  quite  resistant.  Apparently 
the  only  conditions  under  which  the  disease  can  exist  are 
extremely  poor  drainage  and  very  wet,  heavy  soil  about 
the  roots.  Badly  diseased  trees  are  difficult  to  revive  but 
may  be  replaced  provided  the  soil  conditions  are  improved. 


Diseases  and  their  Control  373 

The  use  of  sour  orange  stocks  together  witli  good  drainage 
and  aeration  of  the  soil  are  the  l)est  methods  of  prevention. 

Toadstool  Root  Rot 

Most  mushrooms  grow  only  on  dead  material  hut  there  are 
some  which  are  actually  parasitic  on  living  plants.  The 
mushroom  known  as  Armillaria  mellea  has  caused  heavy 
losses  of  fruit  trees  both  in  Europe  and  America.  The 
fungus  is  native  to  the  roots  of  oak  and  some  other  trees  and 
occurs  most  commonly  on  lands  previously  occupied  by  oak 
trees.  After  the  oak  trees  are  cut  down,  the  fungus  lives 
for  some  years  on  the  dead  roots  in  the  soil  and  should  citrus 
trees  be  planted  on  the  land  at  once,  their  roots  are  very  likely 
to  become  infected.  The  fungus  usually  kills  the  tree  in 
from  two  to  four  years,  although  in  some  instances  diseased 
trees  may  remain  alive,  though  unprofitable,  for  an  indefinite 
period.  In  affected  trees,  usually  only  a  part  of  the  top  dies 
at  first,  the  dead  branches  gradually  increasing  in  number. 
If  the  roots  are  examined,  certain  ones  will  be  found  decayed 
and  soft.  Just  under  the  bark  may  be  seen  fan-shaped  pieces 
of  felty  white  fungus  with  the  not  unpleasant  odor  of  fresh 
mushrooms.  Soon  after  a  root  is  attacked  there  may  be 
seen  along  the  side,  and  closely  appressed  to  the  bark,  the 
rhizomorphs  or  long  black  strands  of  the  fungus  which  re- 
semble hay  wire,  although  very  crooked.  During  prolonged 
periods  of  rainy  weather,  the  fungus  sends  up  from  the 
diseased  roots  large  clusters  of  a  dozen  or  more  toadstools 
which  are  brownish  tan  in  color,  six  to  ten  inches  high,  and 
each  one,  where  not  crowded,  three  or  four  inches  broad  on 
top.  Armillaria  lives  only  on  the  roots  of  the  trees  and  can- 
not remain  for  any  length  of  time  in  soil  which  contains 
no  tree  roots.     There  is  no  danger  (as  some  think)  of  in- 


374  Citriis  Fruits 

creasing  the  spread  of  the  fungus  from  tree  to  tree  by  appli- 
cation of  barnyard  manure. 

From  the  nature  of  this  trou!)le  it  is  apparent  that  no  such 
remedy  as  spraying  the  fohage  can  have  the  least  effect  on 
the  disease.  There  is  at  present  no  satisfactory  remedy. 
It  is  not  known  whether  sweet,  sour,  or  pomelo  root  stocks 
are  equally  susceptible.  It  is  urgently  recommended  that 
four  or  five  years  at  least  be  allowed  to  elapse  between  the 
digging  out  of  all  oak  roots  and  the  planting  of  citrus  trees, 
in  order  that  the  fungus  may  die  out.  During  this  time,  the 
land  may  be  planted  to  vegetables  or  alfalfa  if  water  is 
available. 

MotfJed-lcaf 

For  the  past  ten  years  a  very  peculiar  and  baffling  disease 
of  citrus  trees  has  been  gradually  extending  through  southern 
California.  It  is  known  as  mottled-leaf,  and  up  to  the  present 
time  has  been  considered  to  be  a  derangement  of  nutrition 
due  to  physiological  causes.  This  disease  is  probably  the 
most  serious  problem  now  before  the  California  citrus 
growers.  The  injury  to  some  of  the  finest  orchards  in  the 
state  has  amounted  to  millions  of  dollars  in  the  aggregate. 

Mottled-leaf  is  a  kind  of  chlorosis  of  which  there  are  several 
common  on  citrus  trees.  Mottled-leaf,  however,  is  the  only 
form  which  is  widespread  or  very  serious.  The  trouble 
first  appears  as  light  colored  areas  situated  between  the  veins 
of  the  leaves.  The  contrast  between  the  color  of  the  veins 
and  interspaces  is  very  striking.  Mottled  leaves  are  found 
only  towards  the  ends  of  the  shoots  and  represent  leaves 
in  which  the  green  color  has  never  completely  developed, 
rather  than  those  in  which  the  chlorophyll  has  once  existed 
and  then  disappeared.  Leaves  which  are  once  green  never 
become  typically  mottled,  although  they  may  become  lighter 


Disrascs  and  their  Control  375 


Fig.  131. —  Mottled-leaf  di-scase  on  Eureka  lemon. 


376  Ciiru.s  Frnih- 

in  color  or  even  brigyit  yellow,  iis  in  other  forms  of  chlorosis. 
As  the  mottling  increases  there  is  a  decided  shortage  in 
yield  of  fruit  and  in  ])ad  cases  the  fruit  present  is  very 
small,  and  turns  pale  yellow  or  white  when  about  an  inch  in 
diameter.  There  is  considerable  dying  back  of  the  branches 
and  many  sickly  shoots  put  out  along  the  trunk  and  large 
limbs.  In  a  good  many  symptoms  this  disease  is  similar  to 
peach  yellows. 

Mottled-leaf  affects  all  kinds  of  citrus  trees,  regardless  of 
the  kind  of  stock  they  are  budded  upon.  It  affects  other 
trees  also,  including  elm,  maple,  camphor,  eucalyptus,  and 
particularly  Japanese  privet.  The  disease  occurs  in  many 
parts  of  the  world,  but  apparently  it  has  been  seriously  de- 
structive only  in  California.  It  is  quite  general  in  the 
Riverside-Redlands  district,  at  Corona,  Rialto,  Bloomington, 
Pomona,  and  Covina.  In  San  Diego,  Ventura,  and  Santa 
Barbara  counties  it  is  much  less  severe.  It  occurs  in  parts  of 
Tulare  County.  In  the  Sacramento  Valley  it  is  as  yet  ex- 
ceedingly rare  in  spite  of  the  fact  that  many  carloads  of 
slightly  mottled  nursery  trees  from  southern  California  have 
been  set  out. 

A  great  deal  of  scientific  investigation  and  study  has  been 
put  upon  this  disease  and  a  great  many  theories  have  been 
advanced  as  to  the  cause.  Up  to  the  present  time  the  true 
cause  has  not  been  definitely  proven  nor  has  a  satisfactory 
remedy  been  clearly  demonstrated. 

Some  years  ago  the  writer,  working  on  the  hypothesis 
that  mottled-leaf,  like  peach  yellows,  might  be  transmitted 
by  buds  used  in  propagation,  performed  the  following  experi- 
ment :  buds  from  badly  mottled  twigs  of  both  oranges  and 
lemons  were  inserted  in  healthy  sour  orange  stocks.  On  ac- 
count of  the  weakness  of  the  buds  only  a  few  grew,  but  these 
finally  grew  up  into  as  healthy  trees  as  any  in  the  nursery. 


Diseases  and  their  Control 


37' 


This  showed  that  mot- 
tled-leaf is  not  trans- 
mitted by  budding. 

In  1910  R.  R.  Snow- 
den  ^  advanced  the 
theory  that  mottled- 
leaf  was  due  to  an  ex- 
cess of  magnesia  or  an 
improper  ratio  be- 
tween magnesia  and 
lime  in  the  soil. 
Snowden  showed  that 
the  soils  of  some 
healthy  groves  aver- 
aged about  2.5  parts 
of  lime  to  1  of  mag- 
nesia, while  the  soils 
from  sickly  groves 
averaged  1.18  of  lime 
to  1  of  magnesia.  This 
theory  was  much  dis- 
cussed at  the  time, 
but  subsequent  study 
brought  to  light  so 
many  exceptions  to 
the  supposed  rule  that 
the  theory  was  greatly 
weakened.  Heavy  ap- 
plications of  lime 
moreover  have  by  no 
means  proved  a  cure 
for  the  disease. 


Fig.  132.  —  Advanced  stage  of  luottlccl- 
leaf  disease  showing  formation  of  mul- 
tiple buds. 


»  California  Cullivator,  Aug.  11,  1910. 


378  Citrus  Fruits 

Some  prominent  citrus  growers  have  held  that  starvation 
or  a  lack  of  humus  in  the  soil  is  the  cause  of  the  trouble.  In 
answer  to  this  it  may  be  said  that  some  of  the  worst  affected 
groves  in  the  state  are  situated  on  apparently  ideal  soil 
and  are  among  those  best  fertilized  and  otherwise  well  cared 
for. 

Mottled-leaf  is  much  more  prevalent  on  sandy  and  gravelly 
soils  than  on  heavy  adobe  soils.  In  orchards  where  a  certain 
area  or  streak  of  mottled-leaf  runs  through  the  orchard  this 
usually  corresponds  to  an  area  where  the  subsoil  differs 
much  from  the  top  soil,  usually  being  more  coarse  and  open. 
This  has  led  Smith  *  to  conclude  that  "  the  most  prevalent 
and  typical  form  of  mottled-leaf  is  due  to  an  irregular  supply 
of  moisture  and  plant  food." 

In  1912  J.  R.  Hodges,  an  horticultural  inspector  at  Covina, 
California,  noticed  nematode  worms  in  the  soil  near  the 
roots  of  trees  suffering  from  mottled-leaf.  He  advanced  the 
theory  ^  that  the  disease  was  caused  by  these  nematodes. 
The  matter  was  further  investigated  at  the  University  of 
California  Pathological  Laboratory  at  Whittier  where  it 
was  discovered  that  the  nematodes  were  actually  parasitic 
on  the  roots.  E.  E.  Thomas  of  the  laboratory  staff 
published  a  preliminary  report  ^  on  the  distribution  of  nema- 
todes in  the  state  and  the  possible  relation  between  the  worms 
and  the  disease.  The  nematode  theory  was  by  far  the  most 
plausible  of  any  offered  up  to  that  time  and  at  once  attracted 
the  attention  of  many  scientists  to  the  problem,  which  was 
now  attacked  from  an  entirely  new  angle.  The  name  with  a 
description  of  this  nematode  worm  is  given  in  Chapter  XXIV. 

Several  years  will  be  required  for  the  definite  working  out 

1  R.  E.  Smith,  Cat.  Sta.  Bull.  No.  218,  p.  1139. 

2  Cat.  State  Com.  Hort.  Mo.  Bull,  Vol.  II,  No.  6,  p.  555. 

3  University  of  Col.  Agr.  Exp.  Sta.  Cir.,  No.  85,  February,  1913. 


Diseases  and  their  Control  379 

of  the  relation  between  nematodes  and  mottled-leaf.  ISIean- 
wliile  a  great  deal  of  sur\'ey  work  is  being  done.  The  theory 
is  still  held  in  abeyanee  on  account  of  the  fact  that  the  worms 
are  not  always  found  on  the  roots  of  mottled  trees  and  they 
are  occasionally  found  in  small  numbers  on  the  roots  of 
apparently  healthy  trees.  Experiments  are  now  being  carried 
on  with  potted  trees  in  sterilized  soil  which  has  been  inocu- 
lated with  the  nematodes. 

In  May,  1914,  Kellerman  and  Wright  ^  published  the  theory 
that  mottled-leaf  was  commonly  caused  by  nitrogen  star\a- 
tion  following  the  plowing  under  of  mature  straw  rather  than 
a  green  cover-crop.  It  was  explained  that  the  mature  straw 
contained  large  amounts  of  cellulose  and  that  the  molds  and 
bacteria  which  decomposed  the  cellulose  in  the  soil  used  up 
the  available  nitrate  nitrogen  present  in  the  soil.  They 
suggested  further  that  in  maintaining  the  humus  of  citrus 
soils,  green,  succulent  materials  be  used  rather  than  mature 
or  dry  straws.  While  this  theory  appears  to  be  borne  out  by 
greenhouse  experiments  it  is  considered  inadequate  to  ac- 
count for  any  large  proportion  of  the  mottled-leaf  disease  in 
California. 

Perhaps  the  most  plausible  theory  yet  offered  is  that 
recently  published  by  Chas.  B.  Lipman.^  It  is  explained 
that  a  poor  nitrifying  power  on  the  part  of  the  soil,  with  the 
ammonifying  power  remaining  normal,  may  result  in  the 
change  of  practically  all  the  nitrates  in  the  soil  to  ammonia 
compounds.  It  is  further  shown  that  while  some  plants, 
such  as  rice  for  example,  prefer  their  nitrogen  in  the  form  of 
ammonia  compounds,  that  such    compounds    are   actually 

1  Joiir.  Agr.  Research,  Vol.  II,  No.  2,  pp.  101-113. 

2  "The  Poor  Nitrifying  Power  of  Soils  a  Possible  Cause  of 
Die-Back  in  Lemons."  Science,  n.  s.,  Vol.  XXXIX,  No.  1011, 
May  15,  1914. 


380  Citru.'i  Fruits 

poisonous  to  citrus  trees,  which  show  a  decided  preference 
for  nitrates.  With  the  condition  in  the  soil  favoring  slow 
nitrification  and  rapid  ammonification  the  trees  are  forced 
to  take  ammonia  compounds  or  go  without  nitrogen  entirely, 
as  in  many  California  soils  the  ammonia  resulting  from  the 
decomposition  of  organic  matter  is  actually  set  free  in  the  air 
and  lost  entirely.  Experiments  are  now  being  performed 
in  the  hope  of  finding  a  practicable  method  of  treating 
orchard  soils  which  may  accelerate  nitrification  and  at 
the  same  time  retard  ammonification. 


Spot  on  old  lemon  loaf  due  to  withcr-tip. 


Withcr-tlp   (CoUdotrichum  gloeosporioidcs) 

This  disease  is  said  to  be  quite  common  in  Florida  and 
especially  on  limes  in  Cuba,  causing  a  spotting  of  the  old 
fruit  and  leaves,  killing  back  the  twigs,  and  causing  the  young 
newly  set  fruit  to  drop  ofp.^     In  California,  however,  it  ap- 

'  A  recent  investigation  at  the  University  of  California  has 
shown  that  in  Cuba  and  Florida,  two  distinct  diseases  have  been 
confused.  The  killing  and  deforming  of  young  foliage  and  fruits 
of  the  Hme  are  due  to  a  fungus  which  somewhat  resembles  Colleto- 
trichum  gloeosporioides   but   is   entirely   distinct   from   it.     This 


Disca,sfs  and  their  Control  ;i81 

pears  to  be  of  little  practical  importance,  for  although  the 
fungus  has  long  been  present  in  abundance  throughout  the 
citrus  growing  areas,  it  very  rarely  attacks  healthy  trees 
as  an  active  parasite.  On  senile  leaves  or  young  leaves 
weakened  by  fires,  frost,  fumigation,  or  otherwise,  it  causes 
dead  spots,  on  the  surface  of  which  may  be  seen  the  minute 
black  fruiting  bodies  of  the  fungus.  The  fungus  occurs  also 
on  twigs  weakened  from  any  of  the  above  mentioned 
causes.  Trees  suffering  from  gum-disease,  foot-rot,  gopher 
injury,  alkali,  or  from  other  troubles,  often  show  an  abundant 
growth  of  wither-tip.  Spraying  with  bordeaux  mixture  will 
reduce  the  amount  of  the  fungus,  but  perhaps  a  more  logical 
procedure  would  be  to  remove  the  causes  of  weakness  and 
promote  a  healthy  and  disease-resistant  growth.  In  certain 
rare  cases,  especially  in  very  wet,  cold  weather  and  near  the 
coast,  it  is  possible  of  course  that  this  fungus  may  occasion- 
ally act  as  a  true  parasite,  in  which  case  spraying  with 
bordeaux  mixture  is  a  simple  remedy.  Certain  very  small 
red  or  salmon  colored  spots  which  sometimes  occur  on 
lemons  in  Ventura  County  have  ))een  found  to  be  due  to  this 
fungus. 

It  may  be  added  that  chiefly  on  account  of  its  common 
name,  "wither-tip,"  orchardists  are  very  apt  to  refer  to  a 
large  number  of  their  tree  troubles  as  wither-tip  which  are 
in  no  way  attributable  to  CoUctotrichum  glcposporioides. 

new  fungus  has  been  called  Gloeosporium  limeiticolum.  It  causes 
a  very  injurious  disease  of  limes  and  may  attack  lemons  under 
artificial  conditions  but  has  not  been  known  to  do  so  under 
natural  field  conditions.  Oranges  and  pomelos  are  not  attacked. 
Extremely  warm  and  humid  atmospheric  conditions  are  neces- 
sary for  the  development  of  the  fungus,  and  it  is  not  known  to 
occur  in  California.  See  Clausen,  K.  E.,  "A  New  F^'ungus 
Concerned  in  Wither-Tip  of  Varieties  of  Citrus  Medica,"  Phyto- 
pathology II,  6,  217,  December,  1912. 


382  Citrm  Fruits 

When  lemons  which  have  l)een  grown  in  the  warmer  sec- 
tions are  stored  for  a  long  time  they  finally  break  down  with 
a  soft  rot  at  the  center  known  in  the  packing-houses  as  "  old 
age  decay"  or  "core  rot."  The  general  exterior  appearance 
of  the  lemons  may  be  normal,  but  when  pressed  between  the 
fingers  they  collapse.  This  decay  is  not  yet  clearly  under- 
stood but  is  prol)al)ly  due  primarily  to  the  wither-tip  fungus, 
which  usually  kills  the  buttons  after  they  have  been 
weakened  by  age.  Later,  as  the  fruit  ages  and  becomes  less 
resistant  to  encroaching  organisms,  a  species  of  Altcrnaria 
penetrates  the  fruit  by  way  of  the  dead  button,  following 
and  turning  brown  the  central  core  of  pith  and  also  the 
fibrovascular  bundles  as  they  radiate  through  the  spongy 
tissue  of  the  rind.  The  juice  vesicles  seem  to  be  the  last 
to  be  affected.  After  the  vascular  system  is  broken  down 
the  lemons  lose  their  elasticity  and  appear  dead  to  the 
touch.  Fruit  in  such  a  condition  should  not  be  shipped,  as  it 
has  very  poor  carrying  qualities  and  decays  very  quickly  when 
exposed  for  sale  in  warm  weather.  The  chief  remedy  for 
this  trouble  is  to  avoid  allowing  the  fruit  to  ripen  on  the 
trees,  and  to  store  in  houses  where  the  temperature  may  be 
accurately  controlled.  When  the  buttons  succumb  to  wither- 
tip  the  fruit  should  be  closely  watched  and  hurried  to  market 
at  the  first  indication  that  the  fungus  is  entering  the  fruit. 

Twig  blight  (Sclerotinia  Ubertiniana) 

All  kinds  of  citrus  trees  sometimes  exhibit  a  sudden 
withering  and  dying  of  small  twigs  and  occasional  branches 
up  to  one  inch  in  diameter.  The  green  leaves  suddenly 
wither  and  remain  attached  to  the  twig,  which  dies  from  the 
point  of  infection  outward,  and  with  its  dead  leaves  shows 
very  prominently  in  the  green  foliage  of  the  tree  as  though 
it  had  been  broken  and  remained  hanging.     At  the  point 


Diseases  and  their  Control  383 

of  infection  a  few  drops  of  gum  usually  form.  During  rainy 
weather  the  sclerotia  (small  black  bodies  a  little  larger  than  a 
grain  of  wheat)  will  often  be  formed  on  the  outside  of  the 
bark  near  the  point  of  infection.  Sclerotia  rarely  form  in 
hot,  dry  weather.  Apparently,  infection  can  only  occur  by 
spores  finding  lodgment  in  abrasions  of  the  bark.  While 
the  spores  of  this  fungus  are  very  plentiful  in  southern 
California,  often  causing  serious  losses  in  the  packing-houses, 
yet  for  reasons  not  at  present  understood,  blighting  of  the 
twigs  is  so  rare  as  to  cause  but  little  damage.  While  the 
casual  observer  may  notice  a  blighted  twig  here  and  there  in 
almost  any  orchard  either  of  oranges  or  lemons,  it  has  never 
been  reported  as  doing  sufficient  damage  to  the  trees  to 
warrant  remedial  measures.  This  trouble  is  very  often 
mistaken  for  wither-tip.  As  a  matter  of  course  all  blighted 
branches  should  be  removed  when  the  trees  are  pruned. 

This  fungus  has  also  been  found  on  the  l)ark  and  roots  of 
old  trees.  The  bark  is  decayed  and,  when  dried  out,  comes 
away  in  fibrous  shreds  very  characteristic  of  this  fungus. 
Remedial  measures  for  this  form  of  the  disease  have  not  been 
worked  out.  Meanwhile  the  treatment  advised  is  to  cut 
away  all  diseased  tissue  and  paint  the  wound  thoroughly 
with  bordeaux  paste. 

Cottony   mold   (Sclrrotinia  lihcrtinicma) 

The  same  fungus  described  above  develops  not  only  on 
citrus  twigs  l)ut  upon  the  vetch  used  as  a  cover-crop  and  on 
orchard  soils.  The  sclerotia  which  form  on  the  twigs  and 
on  the  vetch  finally  dry  and  fall  to  the  ground.  The  following 
rainy  season,  after  being  thoroughly  moistened  they  give 
rise  to  small  funnel-shaped  toadstool-like  bodies  which  produce 
the  spores  of  the  fungus  in  great  quantities.  These  spores 
apparently  require  an  abrasion  in  order  to  germinate  and 


884 


Citni.i  Fruits 


grow  in   the  fruit.     Once  the  fungus  has  begun  growth  in 
a  lemon  its  progress  is  rapid.     A  hirge  amount  of  white 


Fig.  134.  —  A  "  nest  "  of  cottony  fungu.s 


cotton-Uke  myeehum  is  produced  in  which  the  characteristic 
black  sclerotia  are  formed.     An  important  point  to  l)ear  in 


Diseases  and  their  Control  385 

mind  is  the  fact  tliat  wliile  the  spores  of  the  fungus  require 
an  abrasion  for  inocuhition,  the  white  mycelium  is  abun- 
dantly able  to  grow  into  and  infect  a  perfectly  sound  lemon 
at  any  point.  The  decay  is  often  very  serious  in  stored 
lemons,  the  fungus  spreading  rapidly  in  all  directions  from 
the  lemon  originally  infected.  Unless  discovered  and  re- 
moved in  time  cottony  mold  often  destroys  an  entire  half- 
box  or  even  a  whole  stack  of  stored  lemons.  For  this 
reason  packing-house  men  are  always  on  the  watch  for 
"nests"  of  the  cottony  fungus,  carefully  removing  the 
source  of  infection  as  soon  as  discovered,  and  disinfect- 
ing the  contaminated  boxes  vnth  very  strong  bluestone 
solution. 

The  disinfecting  solution  used  in  the  wash-water  against 
brown  rot  does  not  kill  the  thicker  walled  spores  of  this 
fungus;  in  fact,  bluestone  solution  of  sufficient  strength  to 
kill  the  spores  would  produce  serious  spotting  of  the  lemons. 
Preventive  measures  must  therefore  be  taken  in  the  orchard 
when  the  lemons  are  picked.  It  is  suggested  that  the  lug- 
boxes  be  placed  on  bare  grovmd  or  at  least  not  left  standing 
for  days  in  the  vetch  where  the  spores  of  the  fungus  are  pro- 
duced. Empty  boxes  so  placed  may  easily  become  dusted 
with  spores,  and  inasmuch  as  it  is  the  custom  in  many  houses 
to  submerge  the  full  lug-boxes  in  the  wash-water  as  the 
lemons  are  gently  emptied,  the  spores  are  reaflily  transferred 
to  the  water.  The  cut  surface  of  the  stem  of  the  lemon  where 
it  was  severed  from  the  tree  affords  ample  opportunity  for 
spore  infection  in  the  washing-tank. 

Cottony  mold  is  most  severe  on  lemons  and  occurs  sporadi- 
cally, being  worse  in  certain  sections  and  in  certain  years. 
It  may  be  wise  to  temporarily  discontinue  the  use  of  vetch 
as  a  cover-crop  in  orchards  where  cottony  mold  has  become 
well  established. 

2c 


386  Citrus  Fruits 


Broum   rot  fruit  decay   {Pythiacystis  citrophthorn) 

It  has  been  shown  that  tliis  fungus  causes  gum-disease  of 
the  tree.  It  also  causes  a  serious  decay  of  the  fruit.  The 
fungus  hves  normally  in  the  soil  even  at  considerable  depths. 
It  comes  to  the  surface  during  wet  weather  in  winter  and 
produces  spores  on  the  surface  of  the  ground,  especially 
in  damp,  shady  places,  such  as  under  citrus  trees.  The 
spores  are  motile  and  can  swim  around  in  a  thin  film  of  water. 
The  drip  from  the  tree  splashes  these  spores  upon  fruit  hang- 
ing within  two  or  three  feet  of  the  ground.  The  spores 
enter  the  stomata  or  breathing  pores,  germinate,  and  grow 
within  the  fruit,  producing  a  soft,  watery  decay  which  has  a 
peculiar  brown  color  and  a  characteristic  odor.  All  citrus 
fruits  are  affected,  but  lemons  are  especially  susceptible. 
During  wet  winters,  the  losses  from  this  cause  are  often  very 
great.  The  decay  spreads  rapidly  in  the  packing-house  as 
the  mycelium  is  able  to  infect  perfectly  sound  fruit  by  con- 
tact. If  not  discovered  and  removed,  the  decay  starting 
from  one  lemon  may  run  through  an  entire  box  or  a  stack  of 
boxes  in  storage,  and,  in  a  short  time,  reduce  the  whole  to 
a  watery  mass. 

Fortunately  a  simple  and  very  effective  remedy  is  now  in 
use  in  all  packing-houses.  The  spores  of  the  fungus  being 
very  thin  walled  are  extremely  susceptible  to  copper  sulfate, 
and  in  order  to  free  any  packing-house  of  this  pest  it  is  only 
necessary  to  add  bluestone  to  the  wash-water.  The  common 
practice  is  to  add  1|  pounds  of  bluestone  to  each  1000  gallons 
of  water  in  the  morning  and  then  fortify  this  with  an  addi- 
tional pound  at  noon  after  considerable  fresh  water  has 
entered  the  tank.  As  bluestone  attacks  metal,  wooden  or 
cement  tanks  should  be  used.  Some  prefer  metal  tanks 
coated  with  asphaltum.      Should   the   wash-water    contain 


Diseases  and  their  Control  387 

alkali  the  hluestone  may  be  neutralized,  and  in  such  cases  a 
chemist  should  be  employed  to  study  the  water  and  advise 
as  to  the  proper  procedure  to  keep  the  solution  of  bluestone 
as  near  as  possible  at  a  strength  of  5^0^  of  one  per  cent. 

In  order  to  reduce  to  a  minimum  the  loss  of  lemons  on  the 
trees  it  is  advisable  to  keep  the  branches  pruned  up  some- 
what from  the  ground,  and  summer  cultivation  should  extend 
well  under  the  trees.  It  has  been  found  well  worth  while 
also  to  spray  the  ground  under  the  trees  each  fall  before 
the  rains  begin  with  bordeaux  mixture,  as  this  largely  pre- 
vents the  fungus  from  fruiting  at  the  surface  of  the  ground. 

Blue  mold  (Pcnicillium  itaJicum)  arid  green  mold 
(P.    digitatum) 

Most  of  the  decay  of  citrus  fruit  is  due  to  blue  and  green 
molds.  Being  only  very  slightly  parasitic  on  uninjured  fruit, 
the  decay  is  practically  confined,  under  ordinary  conditions, 
to  fruit  which  has  been  injured  in  handling.  The  spores  of 
these  fungi  are  very  common  in  the  air  everywhere  and 
are  almost  sure  to  get  into  any  slight  abrasion  of  the  skin 
of  fruit.  They  produce  a  soft  rot  while  the  fungi  fruit 
abundantly  over  the  surface,  the  spores  appearing  as  a  blue 
or  a  greenish  powder  according  to  which  species  is  present. 
Frequently  the  two  kinds  occur  together,  although  the  green 
is  the  most  universal.  For  all  practical  purposes  these  two 
species  of  penicillium  may  be  treated  as  one.  About  the 
only  difference  is  the  color  of  the  spores  and  the  fact  that  in 
pure  culture  the  blue  mold  shows  a  wider  l)and  of  white 
exposed  mycelium  between  the  fruiting  area  and  the  sound 
skin.  The  universal  preventive  for  these  decays  is  careful 
handling  of  the  fruit  in  field  and  packing-house,  which, 
if  conscientiously  enforced,  will  reduce  the  losses  to  a 
minimum. 


388 


Citrus  Fruits 


Gray  mold  (Botrytis  vulgaris) 

Occasionally  lemons  while  in  storage  will  develop  what  is 
known  as  gray  mold.  It  appears  as  a  dark  brown  discolora- 
tion and  softening  which  is  followed  by  the  mycelium  which 
appears  at  the  surface  and  produces  gray  or  mouse- 
colored  spores.  The  fungus  is  apparently  dependent  on 
abrasions  for  access  to  the  fruit  and  would  no  doubt  be 
much  more  abundant  were  it  not  for  the  fact  that  the  blue 
and  green  molds  usually  monopolize  such  opportunities  for 
development. 


Black  rot  of  Navel  orange  (Altcrnaria  citri) 

Navel  oranges  only  are  subject  to  black  rot  which  may  be 

recognized  by  the 
premature  ripening, 
abnormally  large 
size,  and  very  deep 
red  color.  The 
affected  fruits  are 
very  conspicuous  on 
the  trees  liefore  the 
main  crop  has  col- 
ored up.  The 
spores  of  the  fungus 
gain  entrance  at  the 
navel  end  through 
slight  imperfections 
of  the  peel  or  per- 
haps through  the 
stigma  of  the  blos- 
som, and  produce  a  black,  decayed  area  under  the  skin. 
This  decay  does  not  immediately  spread  through  the  entire 


Fig.  135.  —  Black  rot  of  Navel. 


Diseases  and  their  Control  389 

fruit,  but  remains  for  weeks  as  a  small  black  mass  of  fungus. 
Decayed  tissue  may  occasionally  extend  to  the  surface,  but 
more  often  this  is  not  the  case  and  the  fruit  finds  its  way 
into  the  hands  of  the  consumer. 

There  is  no  known  remedy  for  this  trouble  which  occa- 
sionally affects  as  much  as  one  per  cent  of  the  crop  in  certain 
localities.  It  is  suggested,  however,  that  all  affected  fruits 
should  be  gathered  up  and  burned  in  order  to  reduce  the  num- 
ber of  spores  in  the  orchards. 

Brown  spot  of  Navel  orange 

The  brown  spot  of  the  Navel  orange  may  be  described  as 
occurring  irregularly  over  the  surface  of  the  orange.  From 
one  to  fifty  or  more  spots  may  develop  on  a  single  fruit.  The 
spots  vary  in  size  from  a  mere  point  to  one  inch  in  diameter, 
averaging  about  one-fourth  inch.  In  outline  they  seem  to 
follow  no  rule  and  may  be  quite  irregular,  although  the  cir- 
cular spot  is  most  common.  The  color  of  the  spot  varies  in 
different  localities  from  a  pale  brown,  which  attracts  little 
notice,  to  almost  black,  in  which  case  the  good  appearance 
of  the  fruit  is  ruined.  The  eating  qualities  of  spotted  oranges 
are  not  injured  in  the  least.  The  color  of  the  spot  seems  to 
be  lighter  near  the  coast  and  darker  in  the  interior  valleys. 
Losses  from  brown  spot  have  been  heaviest  from  the  upper 
San  Gabriel  and  Santa  Ana  valleys,  because  in  these  regions 
the  spotting  is  more  common  and  the  color  changes  to  a  darker 
brown.  On  the  other  hand,  the  fruit  from  many  of  the  pack- 
ing-houses near  the  coast  shows  brown  spots  of  such  a  pale 
tint  as  to  attract  no  notice  on  the  market.  The  spots  are 
darker  on  early  picked  fruit,  and  it  seems  to  be  true  that  if 
the  fruit  is  left  on  the  trees  until  very  late  it  will  not  spot  at 
all.  The  spots  are  slightly  sunken  on  account  of  the  fact 
that  the  surface  cells  have  collapsed.     The  dead  and  col- 


390 


Citrus  Fruits 


lapsed  tissue  extends  from  the  surface  to  about  one-fourth 
the  thickness  of  the  rind.  No  spots  are  visible  while  the  fruit 
is  on  the  trees  and  as  a  rule  the  spots  are  not  noticeable  till 
from  15  to  25  days  after  picking.  On  this  account  it  is  not 
possible  to  grade  against  this  spot  in  the  packing-houses, 
unless  storage  houses  of  sufficient  capacity  are  built  to  hold 

the  pickings  of   three 
or  four  weeks. 

The  brown  spot  has 
l)een  observed  so  far 
chiefly  on  the  Wash- 
ington Navel  orange, 
and  dealers  have  com- 
plained of  it  only  on 
this  variety.  In  1914 
the  writer  received 
specimens  of  Valencia 
oranges  from  Highland 
which  had  been  picked 
about  the  first  of  June 
which  showed  almost 
typical  brown  spot. 
The  color  was  lighter  and  less  damaging  than  usually  occurs 
on  the  Navel.  Spotting  is  uniformly  worse  on  fancy, 
smooth,  thin-skinned  fruit.  The  fruit  which  grades  highest 
as  it  comes  from  the  orchartl  always  spots  much  more  than 
the  rough  fruit,  which  often  remains  exempt.  Examination 
of  the  spots  with  a  hand  lens  fails  to  show  any  abrasion  or 
opening  in  the  epidermis. 

Orange  packers  have  been  complaining  of  the  brown  spot  for 
only  four  or  five  years,  but  it  is  probable  that  it  has  existed, 
though  varying  in  severity,  as  long  as  the  Navel  orange  has 
been  cultivated  in  California. 


Fig.  136.  — Brown  spot  of  Navel  orange. 


Diseases  and  their  Control  391 

Up  to  the  present  time  neither  the  primary  cause  nor  a 
remedy  has  been  discovered.  After  an  extended  investiga- 
tion the  writer  was  led  to  conchide  ^  "  That  the  direct  cause  of 
brown  spot  is  the  oxidation  of  the  protophism  by  enzymes 
which  occur  in  the  protoplasm  itself  but  which  are  prevented 
from  acting  as  long  as  the  orange  is  joined  to  the  tree  and 
receiving  water  and  certain  nutritive  substances  from  the 
tree.  Thus  the  resistance  of  the  protoplasm  to  enzyme  en- 
croachments gradually  grows  less  from  the  time  the  orange 
is  picked."  This  conclusion  merely  takes  the  real  question 
one  step  farther  back,  for  the  practical  citrus  men  will,  of 
course,  wish  to  know  the  primary  causes  which  bring  about 
such  premature  death.  This  question  cannot  be  answered  at 
the  present  time. 

Damping-off  (Rhizodonia  sp.  and  Fusarium  sp.) 

Citrus  seed-beds  are  often  seriously  injured  by  damp-oflF 
fungi.  The  very  young  plants  begin  to  die  in  spots  which, 
rapidly  extending,  involve  large  areas  if  not  checked.  Two 
forms  of  the  disease  are  recognizable,  one  caused  by  the 
Rhizoctonia  which  kills  the  stem  just  above  the  ground,  while 
the  other  shows  itself  in  dead  spots  on  the  stem  at  any  point. 

These  troubles  should  be  prevented  by  strict  attention  to 
proper  methods  of  planting  and  watering.  No  manure  or 
freshly  decaying  organic  matter  should  be  applied  to  the 
seed-bed,  commercial  fertilizers  being  used  exclusively.  The 
seed  should  be  covered  with  a  layer  of  clean,  fresh  sand  which 
will  prevent  the  surface  from  becoming  too  wet.  For  the 
inexperienced  grower,  particularly,  it  is  better  to  make  wide 
furrows,  two  inches  deep,  about  a  foot  apart,  planting  the 
seed  broadcast  on  the  ridges  between.     The  water  may  then 

'  "The  Brown  Spot  of  the  Navel  Orange,"  Proc.  Soc.  for 
Hort.  Set.,  1900. 


392  Citru.s  Fruits 

be  run  in  these  furrows  and  allowed  to  soak  into  the  ground 
laterally,  thus  keeping  the  surface  of  the  sand  dry.  ^Yhere 
the  seed  is  sovm.  broadcast  over  the  whole  surface  of  the  bed 
and  the  water  applied  by  sprinkling,  watering  should  always 
be  done  on  sunny  mornings  and  no  oftener  than  is  absolutely 
necessary.  In  most  cases  a  good  watering  once  a  week  is 
sufficient  to  keep  the  soil  under  the  sand  sufficiently  moist. 
Should  the  seedlings  begin  to  damp  off  in  spite  of  all  precau- 
tions, it  is  advisable  to  allow  the  bed  to  go  as  dry  as  is  reason- 
ably safe,  and  then  spray  the  surface  of  the  bed  with  a  rather 
weak  bordeaux  mixture,  being  careful  to  wet  the  entire  surface 
of  the  soil. 

Citrus  Canker 

Very  recently  a  new  disease  has  appeared  in  the  Gulf  States 
which  is  described  as  the  most  serious  which  affects  the 
pomelo.  Sweet  oranges  are  apparently  immune.  It  exists 
in  Florida  and  Alabama,  the  first  specimens  being  collected 
in  1912.  So  far  it  has  not  been  reported  from  California. 
H.  E.  Stevens  describes  the  trouble  as  follows:^  "The 
disease  appears  as  small,  circular  spots,  from  less  than  one- 
sixteenth  to  one-quarter  of  an  inch  across.  They  may  occur 
singly,  or  several  together  may  form  an  irregular  area.  They 
are  raised  above  the  surrounding  tissue,  are  light  brown,  and 
composed  of  a  spongy  mass  of  dead  cells  covered  by  a  thin 
(white  to  grayish)  membrane  that  finally  ruptures  and  turns 
outward,  forming  a  ragged  margin  around  the  spot.  The 
general  appearance  of  the  spots  is  much  the  same  whether 
they  are  found  on  the  leaves,  fruit,  or  twigs.  The  older 
spots  often  become  overgrown  with  saprophytic  fungi,  and 
may  be  pink  or  black  on  account  of  secondary  infection  by 
species  of  Fusarium  or  Cladosporium. 

1  "Citrus  Canker."  H.  E.  Stevens,  Florida  Exp.  Stn.  Bull. 
No.  122,  1914. 


Diseases  and  their  Control  393 

"The  infections  on  the  leaves  appear  first  as  small  watery 
bulging  (lots,  which  are  usually  of  a  darker  green  than  the 
surrounding  tissue.  They  may  appear  on  either  surface 
of  the  leaf,  but  do  not  penetrate  through  the  leaf  tissue  at 
this  stage.  The  spots  gradually  increase  in  size,  change  to 
a  light  brown  color,  and  become  visible  on  both  sides  of  the 
leaf.  The  spot  may  project  from  the  surface  on  one  or  both 
sides  of  the  leaf.  Each  spot  is  surrounded  by  a  narrow  yel- 
lowish band  or  zone.  Later  the  surface  of  the  spot  becomes 
white  to  grayish,  and  finally  ruptures,  exposing  a  light-brown 
spongy  central  mass. 

"The  spots  on  the  fruit  are  similar  to  those  on  the  leaves. 
They  project  from  the  surface  and  retain  a  circular  outline. 
They  do  not  penetrate  far  into  the  rind,  and  may  be  scattered 
singly  over  the  surface,  or  several  may  occur  together,  forming 
irregular  masses. 

"The  spots  on  the  older  twigs  are  more  prominent  and 
usually  larger  and  more  irregular  in  shape.  They  show  the 
same  spongy  tissue  and  the  same  color  as  those  on  the  leaves. 
On  growth  more  than  a  year  old,  the  spots  assume  a  cankerous 
appearance  and  the  membrane  covering  the  surface  disap- 
pears. The  spots  do  not  penetrate  to  the  wood,  but  are  con- 
fined to  the  outer  tissues  of  the  bark. 

"The  organism  causing  the  disease  has  not  been  deter- 
mined, but  it  is  probably  a  fungus.  Several  different  fungi 
have  been  found  associated  with  the  spots,  among  which  a 
species  of  Phyllostida^  occurs  most  frequently.  This  fungus 
is  suspected  of  being  the  cause  of  the  trouble,  and  experi- 
ments are  now  in  progress  to  determine  this. 

"The  disease  is  infectious,  as  is  shown  by  the  results  of 
some  experiments  in  which  it  was  transferred  from  diseased 
material  to  healthy  leaves  and  shoots  of  grapefruit." 

'  Later  found  to  be  a  species  of  Phoma.  See  Wolf  and  Massey, 
Circular  27,  Alabama  Experiment  Station. 


394  Citrm  Fruits 

Control  measures  have  not  yet  been  fully  worked  out. 
On  account  of  the  presence  of  this  fungus,  the  state  of  Florida 
is  now  quarantined  against  the  introduction  of  nursery  stock 
or  bud-wood  from  Alabama. 

Melanose  and  Stein  End  Rot  (Phomopsis  citri) 

These  diseases,  which  are  both  caused  by  the  same  fungus, 
have  been  prevalent  in  Florida  for  many  years.  The  fungus 
occurs  in  Australia,  Jamaica,  Porto  Rico,  and  Algeria,  but  so 
far  has  not  been  found  to  exist  in  California. 

The  disease  lives  normally  and  produces  spores  on  dead 
twigs  in  citrus  trees.  The  spores  are  washed  by  the  rains 
over  the  surface  of  the  fruit,  causing,  particularly  on  pomelos, 
peculiar  brownish  streaks  known  as  tear-staining  or  melanose. 
These  marks  are  nearly  the  same  on  leaves,  stems,  and  fruit, 
and  consist  of  raised  areas  of  brown  gum-filled  cells  forming 
dots,  lines,  rings,  or  irregular  spots  which  greatly  injure  the 
general  appearance  of  the  fruit  while  not  injuring  the  eating 
quality. 

Stem-end  rot  causes  the  fruit  to  drop,  beginning  with  im- 
mature fruit  in  August  and  continuing  till  after  the  fruit  has 
been  sent  to  market.  It  even  causes  decay  after  the  fruit 
has  reached  market.  The  softening  begins  at  the  stem 
end  and  is  especially  common  on  fruits  which  have  scale 
insects  about  the  stem  end.  It  is  more  severe  during  a  warm 
fall  and  winter,  and  infection  seems  to  be  more  common  in 
damp  shady  situations.  Sound  picked  fruit  can  be  infected 
by  contact  with  diseased  fruit.  The  fungus  inhabits  the 
soil  under  infected  trees  and  the  spores  develop  in  spring 
and  summer  on  dead  twigs,  bark,  and  on  mummified  fruits. 

The  application  of  fungicides  to  the  trees  or  disinfectants 
to  the  wash-water  does  not  control  the  disease.  The  most 
successful  method  of  control  is  to  keep  the  trees  carefully 


Diseases  and  their  Control  395 

pruned  and  free  from  all  dead  twigs,  stubs,  and  mummified 
fruits.  The  prunings  should  not  be  plowed  into  the  soil,  but 
should  be  removed  from  the  orchard  and  burned  before  the 
fungus  has  time  to  grow  and  produce  spores  upon  this  ma- 
terial. All  diseased  fruit  which  falls  to  the  ground  should  be 
collected  and  destroyed.  Careful  culling  at  the  packing- 
house and  refrigeration  in  transit  are  aids  to  control.  Also 
it  is  advisable  to  keep  the  trees  as  free  as  possible  from 
scale  insects. 

Nail-head  Rud   (Cladosporium  herbarum  var.   ciiricolum) 

In  Florida  the  nail-head  rust  is  quite  common,  while  it  has 
not  as  yet  been  found  in  California.  It  is  often  called  scaly- 
bark  in  Florida,  but  it  is  very  distinct  from  the  California 
scaly-bark,  the  cause  of  which  has  not  yet  been  discovered. 
The  disease  appears  on  the  twigs  and  small  branches  as 
slightly  raised  rusty  spots,  as  implied  by  the  name.  The 
fungus  also  produces  spots  on  the  fruits  which  are  hard,  cir- 
cular, sunken,  and  more  or  less  corky.  Affected  fruits  color 
and  drop  prematurely.  The  spots  due  to  this  fungus  are 
found  only  on  sweet  oranges.  Various  control  measures 
have  been  suggested,  such  as  top-working  the  trees  to  pome- 
los ;  heading  back  and  spraying  with  bordeaux,  followed  by 
an  insecticide ;   and  carefully  pruning  out  all  dead  wood. 

Scab  or   Verrucosis   {Cladosporium  citri) 

Citrus  scab  is  another  disease  which  occurs  in  Florida  and 
other  parts  of  the  world  but  has  not  so  far  been  found  in 
California.  The  following  description  of  scab  is  from  the 
Florida  Experiment  Station  Bulletin  No.  108,  page  41. 

"  This  disease,  which  is  especially  common  on  sour  oranges 
and  lemons,  makes  its  appearance  on  the  fruit  as  irregular 


396  Citrus  Fruits 

light  brown  or  corky  projections  from  the  surfac(\  It  is 
caused  by  a  fungus  which  attacks  the  fruit  or  lea\'es  when 
quite  young.  Its  attack  on  sour  oranges  and  lemons  (and 
sometimes  on  Satsumas  and  grapefruit)  often  results  in 
making  them  misshapen  and  unsightly.  In  severe  attacks, 
projections  of  a  dark  gray  to  corky  or  even  tan  color  will  be 
seen  extending  out  from  the  surface.  The  surface  of  the 
fruit  between  the  warts  is  usually  of  a  normal  color.  Often 
these  irregular  corky  projections  coalesce  to  form  a  large 
raised  corky  scab.  In  less  severe  attacks,  especially  when 
scab  occurs  on  grapefruit  and  on  tangerines  (or  rarely  on 
sweet  oranges),  the  warty  irregular  projections  are  wanting, 
and  there  will  be  seen  more  or  less  raised  platform-like 
patches  variable  in  shape  and  extent.  The  surface  of  the 
raised  portion  is  finely  scabbed  or  lightly  scurf ed,  as  is  seen 
in  the  case  of  thrips  marks  or  silver  scurf.  In  this  milder 
form  it  can  usually  be  distinguished  from  thrips  marks  or 
other  forms  of  scurf  by  its  being  raised,  but  can  be  distin- 
guished with  certainty  only  by  the  use  of  the  compound 
microscope. 

"  The  scab  can  be  completely  controlled  by  the  use  of  weak 
bordeaux  mixture  (3-3-50).  Since  (in  Florida)  the  use  of 
bordeaux  on  orange  trees,  however,  kills  the  friendly  fungi  ^ 
and  allows  a  rapid  increase  of  scale  insects  or  white-fly,  this 

1  It  should  be  explained  for  the  benefit  of  those  not  famiHar 
with  eonditions  in  Florida  that  there  are  a  number  of  Idnds  of 
fungi  wliich  prey  as  parasites  upon  the  scale  insects  and  white-fly 
larvae  and  are  thus  of  very  great  benefit  to  the  citrus  growers. 
Some  of  these  friendly  fungi  occur  in  India  and  other  places, 
but  so  far  none  have  been  successfully  estabhshed  in  California, 
where  the  air  is  too  dry  perhaps  for  their  success.  In  spraying 
with  bordeaux  for  fungus  diseases  in  Florida,  the  killing  off  of 
these  friendly  fungi  has  to  be  considered,  for  an  application  of 
bordeaux  usually  must  be  followed  by  an  insecticide  on  account 
of  the  great  sudden  increase  of  scale  insects. 


Diseases  and  their  Control  397 

spray  is  not  recommended  except  when  it  is  absolutely  neces- 
sary. When  it  must  be  resorted  to,  a  good  insecticide  should 
be  used  as  soon  as  the  scale  insects  begin  to  increase  rapidly. 
Some  of  the  harm  from  increase  of  scale  insects  may  be  pre- 
vented by  spraying  the  bordeaux  as  much  as  possible  only 
on  the  fruit,  and  keeping  the  spray  off  of  the  larger  limbs  and 
the  inside  of  the  tree  where  the  friendly  fungi  may  be  left 
alive." 

Diplodin  Rot  of  Oranges  (Diplodia  natalensis) 

A  form  of  fruit  decay  which  occurs  in  Florida  and  South 
Africa  but  has  not  so  far  been  reported  from  California. 
H.  S.  Fawcett  gives  the  following  description  of  it  in  Florida 
Exp.  Sta.  Bull.  108,  p.  46 : 

"  In  the  early  stage  this  rot  shows  as  a  patch  about  the  stem 
end  similar  to  stem-end  rot.  The  discoloration  becomes 
darker  as  the  decay  proceeds,  and  appears  as  dark  wide  bands 
corresponding  to  the  di\'isions  between  the  segments.  The 
fruit  becomes  black  as  the  decay  advances  and  very  light  in 
weight.  The  rot  often  advances  quickly  through  to  the 
'blossom'  end,  and  a  patch  of  discoloration  shows  there 
before  all  the  peel  is  involved.  The  Diplodia  rot  often 
starts  also  in  thorn  punctures  or  similar  injuries.  It  is 
usually  accompanied  by  the  exudation  of  a  small  amount  of 
thin  gum,  or  a  considerable  amount  of  amber-colored  sticky 
juice.  This  amber-colored  juice  less  frequently  accompanies 
the  stem-end  rot.  IVIany  of  the  characteristics  of  the  two 
rots  are  so  similar  that  for  practical  purposes  they  may  be 
classed  together.  The  citrus  fruits  are  much  more  resistant 
to  Diplodia  rot  than  to  stem-end  rot.  Diplodia  rot  appears 
to  be  less  common  on  immature  fruits  on  the  tree,  and  the 
fungus  causing  it  is  less  parasitic.  The  same  methods  of 
treatment  given  for  stem-end  rot  hold  good  for  the  Diplodia 
rot." 


398  Citrus  Fruits 


Red  Blotch  of  Lemon 

It  is  in  stored  fruit  alone  that  red  blotch  develops.  It  is 
often  called  "red  rot"  by  packing-house  men  but  as  it  is 
apparently  not  due  to  any  parasitic  organism  the  latter  name 
is  misleading.  It  is  characterized  by  the  rind  shrinking  and 
turning  to  a  dark  color  in  large  spots  or  blotches.  The 
discoloration  is  usually  limited  to  one  side  of  the  fruit  and 
gradually  changes  from  rusty  bronze  to  dark  red  and  finally 
to  black.  On  cross  section,  affected  fruit  shows  the  discolora- 
tion about  the  seeds,  the  central  core,  and  along  the  parti- 
tions, while  the  vesicles  appear  normal.  The  disease  does 
not  spread  among  the  lemons  by  contact.  It  is  unusual 
for  red  blotch  to  develop  in  large  amount  in  any  one  house, 
although  the  losses  in  the  aggregate  are  large.  It  has  been 
suggested  that  red  blotch  may  be  caused  by  sunburn  or 
overheating  of  the  lemons  on  the  tree,  but  so  far  neither  the 
true  cause  nor  a  remedy  has  been  demonstrated. 

Yellow  Spottiufi  of  Oranges 

In  all  the  interior  valleys  of  southern  and  central  California 
and  in  Arizona  it  is  the  usual  thing  for  oranges  of  all  varieties 
to  develop  small  bright  yellow  spots  before  the  oranges  are 
mature.  Often  these  spots  are  very  conspicuous  on  account 
of  the  contrast  with  the  green  rind.  Usually  all  the  oranges 
on  the  exterior  of  the  trees  and  especially  those  near  the 
ground  show  the  spots.  When  the  fruit  colors  naturally 
there  is  no  longer  any  contrast  and  the  spots  are  no  longer 
visible  to  any  but  an  experienced  eye.  As  these  spots  do  not 
damage  the  fruit  for  eating  or  for  sale  but  little  interest 
has  been  shown  in  determining  the  cause.  They  are  probably 
due  to  the  bites  of  some  small  insect  such  as  a  leaf-hopper, 
many  species  of  which  are  common  in  the  orchards.     At 


Diseases  and  their  Control 


399 


one  time  it  was  thought  that  these  spots  later  developed  into 
the  brown  spot  of  the  Navel  orange,  but  this  has  been  shown 
not  to  be  the  case. 

Stem  End  Spot 

The  California  stem  end  spot  of  oranges  is  a  very  different 
thing  from  the  stem  end  rot  common  in  Florida  aiid  pre- 
viously described.  It 
appears  as  small  dried 
out  and  sunken  spots 
immediately  adjacent 
to  the  stem  of  the 
fruit  and  is  most  seri- 
ous on  the  Navel 
orange.  It  occurs 
only  on  fruit  which  is 
beginning  to  age.  The 
cause  has  not  been 
clearly  demonstrated. 
Sometimes  during  wet 
weather,  saprophytic 
fungi  may  grow  on 
these  dead  spots,  in 
which  case  the  appear- 
ance of  the  fruit  is  injured  and  it  is  not  safe  to  ship  it  to 
market.     The  remedy  is  to  pick  and  ship  the  fruit  earlier. 


Trunk  Rot  {Schizopyllum  commune) 

The  decay  of  the  trunks  of  citrus  trees  due  to  this  fungus  is 
especially  common  in  the  moist  coast  region  and  in  northern 
California.  Where  stubs  have  been  left  in  careless  pruning  of 
the  large  limbs  the  spores  gain  entrance,  and  in  time  the  white 
bracket-like  fruiting  bodies  appear.     The  fungus  is  thought 


400 


Citrus  Fruits 


not  to  be  strongl}-  parasitic  on  sound  healthy  tissue,  hut  once 
started  it  may  cause  dying  l)ack  of  the  wooch  The  disease 
may  easily  be  prevented  by  paying  proper  attention  to  the 


•'^Uk.isJ 

B^ijar^^ 

^30) 

in3 

m 

j^^^ei 

W' 

M^j 

wr 

'^^J3^ 

m 

Fig.  13s.  —  Pruning  stub  on  orange  tree  affected  with  Schizopyllum. 


disinfection  of  pruning  wounds  and  by  covering  all  large 
cuts  with  a  suitable  dressing.  Inasmuch  as  the  presence  of 
this  fungus  indicates  neglect,  it  reflects  discredit  upon  the 
orchardist. 

There  are  several  other  kinds  of  fungi  which  have  not  been 
identified  which,  after  getting  started  in  sunburn  cracks  or 


Diseases  and  their  Control  401 

frost  injuries,  may  cause  a  progressive  decay  of  the  wood 
of  citrus  trees.  All  these  may  be  prevented  by  care  and 
attention  to  injuries.  When  once  well  started  it  may  require 
rather  extensive  tree-surgery  to  entirely  rid  the  tree  of  the 
infection.     • 

Galls  and  Knots 

Occasionally  large  galls  are  found  on  the  branches  of  citrus 
trees  in  California.  They  are  not  common  or  very  injurious, 
and  the  only  remedy  suggested  is  to  prune  them  out.  These 
galls  may  be  due  to  the  crown  gall  organism  which  produces 
similar  galls  on  the  roots  of  peach,  almond,  and  other  fruit 
trees.  Crown  gall  has  been  produced  on  citrus  trees  experi- 
mentally by  C.  O.  Smith  of  the  University  of  California. 

Recently  Florence  Hedges  ^  investigated  a  rather  serious 
and  contagious  form  of  gall  on  citrus  trees  from  the  Island  of 
Jamaica.  The  cause  was  discovered  to  be  a  fungus,  Spha'rop- 
sis  tumefaciens.  All  the  galls  so  far  found  in  California 
have  been  different  and  the  contagious  SplioBrojisis  gall  is  not 
known  to  occur  either  in  California  or  Florida,  although 
common  in  Cuba. 

Black  Pit  of  Lemon   (Bacterium  citriputeole) 

A  serious  blemish  which  occurs  occasionally  on  tree-ripe 
lemons  late  in  the  spring.  This  trouble  is  apparently  con- 
fined to  southern  California.  It  appears  as  large  dark  red 
or  black  spots,  the  surface  of  which  is  firm  and  markedly 
depressed  below  the  general  surface  of  the  rind.  The  spots 
do  not  increase  in  size  rapidly  or  progress  into  a  general 
decay,  but  the  appearance  of  the  fruit  is  ruined.     The  cause 

'  "A  Knot  of  Citrus  Trees  Caused  by  Sphceropsis  tumefaciens  " 
by  Florence  Hedges  and  L.  S.  Tenny,  U.  S.  D.  A.  Bureau  Plant 
Industry,  Bull.  No.  247,  1912. 
2d 


402  Citrus  Fruits 

is  a  bacterium  which  gains  access  to  the  rind  through  thorn 
punctures.  Apparently  an  abrasion  is  necessary  before  the 
bacteria  can  enter.  The  trouble  may  be  prevented  in  three 
ways :  pick  the  fruit  before  it  becomes  tree-ripe,  grow 
thornless  varieties,  or  protect  the  orchard  by  windbreaks. 


CHAPTER   XXII 
CITRUS  INSECTS  AND   THEIR  CONTROL 

The  number  of  insects  which  seriously  attacls:  citrus 
fruit  trees  in  California  is  not  large  ;  their  lack  in  numbers, 
however,  is  more  than  offset  by  their  aggressiveness  and 
their  ability  to  withstand  control  measures.  While  it  is 
true  that  fumigation  for  scale  and  spraying  for  red  spider 
or  mites,  if  properly  done,  is  supposed  to  kill  all  the  in- 
dividuals on  the  trees  at  the  time  of  treatment,  yet  in  actual 
practice  a  few  usually  survive  and  later  reinfest  the  trees, 
so  that  in  the  course  of  time  remedial  measures  must  be 
repeated . 

The  financial  loss  due  to  the  various  citrus  pests  is  large, 
the  cost  of  control  amounting  to  more  than  half  a  million 
dollars  a  year  in  southern  California,  according  to  a  re- 
cent estimate.  This  does  not  take  into  account  the 
secondary  losses  due  to  weakened  trees,  dirty  fruit,  and 
fruit  scarred  by  thrips  or  mites.  The  state  as  well  as  the 
nation  is  spending  large  sums  annually  in  studying  citrus 
pests  and  in  devising  better  methods  of  control,  while  in 
addition  to  this  most  counties  employ  a  horticultural  com- 
missioner and  a  corps  of  inspectors  whose  chief  duty  is  to 
assist  in  controlling  pests  already  established  in  the  county 
and  to  prevent  the  introduction  of  foreign  species. 
403 


404  Citrus  Fruits 

The  distribution  of  the  various  citrus  insects  in  CaUfor- 
nia  is  greatly  influenced  by  the  dift'erent  cHmatic  conditions 
obtaining  in  the  different  parts  of  the  state.  The  purple 
scale  has  so  far  not  become  established  nor  is  the  black 
scale  serious  on  citrus  trees  in  the  hot  dry  air  of  the  interior 
valleys.  The  red  and  yellow  scales  are  both  found  in  the 
San  Joaquin  citrus  districts,  although  not  in  injurious  num- 
bers, while  the  yellow  scale  alone  is  found  in  the  Sacra- 
mento districts.  Before  the  introduction  of  various  in- 
sect pests  into  California  from  Florida,  the  general  opinion 
prevailed  that  such  insects  would  not  thrive  when  taken 
from  a  humid  into  a  comparatively  arid  climate.  The 
fact  that  any  particular  insect  has  not  so  far  become  es- 
tablished in  a  given  region  must  not  be  taken  as  sufficient 
evidence  that  it  will  not  thrive  when  an  opportiuiity  to 
infest  trees  presents  itself. 

At  the  present  time,  it  is  very  encouraging  to  note  the 
fact  that  in  the  better  kept  citrus  orchards  of  the  state 
it  is  often  difficult  to  find  specimens  of  certain  insects  for 
study.  In  some  localities  where  red  and  yellow  scale, 
mealy  bug,  or  silver  mite  were  once  very  abundant,  it  may 
now  require  a  diligent  search  to  locate  a  single  individual, 
so  effective  has  been  the  work  of  the  inspectors  and  the 
application  of  remedial  measures. 

A  point  which  should  be  emphasized  is  the  importance  of 
keeping  orchards  and  fence  rows  free  from  weeds  which 
harbor  scale.  One  of  the  worst  offenders  among  weeds 
is  the  common  nightshade  (Solanum  nigrum)  which  is  so 
abundant  throughout  most  of  the  state.  Even  after 
thorough  fumigation  of  the  trees  has  been  accomplished, 
a  few  scales  living  on  the  nightshade  will  start  a  new  infes- 


Citrus  Insects  and  their  ContrcA  405 

tation,  the  blame  for  whicli  is  often  unjustly  charged  to 
carelessness  of  the  fumigators. 

For  sake  of  convenience,  insects  are  usually  divided  into 
two  general  groups,  the  biting  insects  and  the  sucking  in- 
sects. The  biting  insects  are  those  which  bite  or  tear  oflF 
pieces  of  the  plant  tissue  and  actually  consume  parts  of 
leaves  or  the  tissues  upon  which  they  are  feeding.  The 
sucking  insect  on  the  other  hand  pierces  the  tender  plant 
with  a  slender  proboscis  or  tube-like  mouth-part  and 
proceeds  to  extract  the  sap  from  the  cells.  All  the  scale 
insects,  the  mealy  bugs,  the  plant  lice,  and  the  red  spider 
have  sucking  mouth-parts,  the  thrips  have  mouth-parts 
fitted  for  both  rasping  and  sucking,  while  the  rose 
beetle,  the  orange  tortrix,  and  the  diabrotica  are  biting 
insects. 

A  proper  understanding  of  the  manner  in  which  an  in- 
sect obtains  its  food  is  necessary  before  remedial  measures 
can  be  intelligently  applied.  For  biting  insects,  a  stomach 
poison  such  as  paris  green  or  arsenate  of  lead  should  be 
used,  w^hile  for  sucking  insects,  a  solution  or  gas  which  kills 
by  contact,  such  as  lime-sulphur  or  kerosene  emulsion  or 
hydrocyanic  acid  gas,  is  necessarj^  A  contact  insecticide 
either  fills  up  the  breathing  pores  which  are  located  along 
the  sides  of  the  body  of  the  insect,  thus  suffocating  them,  or 
produces  fatal  irritation.  The  sucking  insects  are  by  far 
the  most  destructive  and  troublesome  in  citrus  orchards 
as  well  as  the  most  difficult  to  control. 

Black  Scale  (Saissrtia  olece) 

The  black  scale  is  widely  distributed  over  the  earth,  since 
like  other  scale  insects,  it  is  very  easily  carried  from  one 


406  Citrus  Fruits 

country  to  another  on  young  nursery  trees  and  ornamental 
plants.     This   scale   is   perhaps   the   most   damaging  insect 


Black  scales  on  orange  tw-ig. 


pest  of  the  citrus  districts  in  the  Mediterranean  region.     The 
exact  date  of  its  introduction  into  California  is  not  known. 


Citrus  Insects  and  their  Control  407 

According  to  a  report  published  in  1880,  it  was  well  es- 
tablished at  that  time.  It  is  found  in  nearly  all  the  counties 
of  the  state,  although  as  a  citrus  pest  it  is  troublesome  chiefly 
in  southern  California,  especially  near  the  coast.  In  Los 
Angeles,  Santa  Barbara,  and  Orange  counties  it  takes  first 
rank  among  citrus  insects,  while  in  Ventura  and  San  Diego 
counties  it  is  given  second  rank.  In  Western  Riverside 
and  San  Bernardino  counties,  it  is  also  a  serious  pest,  as  is 
shown  by  the  fact  that  75  per  cent  of  the  insect  control  work 
in  Riverside  county  in  1910  was  directed  against  the  black 
scale,  although  such  a  high  percentage  is  unusual. 

The  black  scale  injures  the  tree  by  sucking  the  sap.  The 
greatest  injury,  however,  is  done  indirectly  by  the  sooty  mold 
which  accompanies  the  scale.  The  insect  excretes  copious 
amounts  of  a  substance,  known  as  honey-dew,  which  falls 
upon  the  leaves  and  fruit  below.  This  furnishes  a  suitable 
medium  for  the  growth  of  the  sooty  mold  fungus  (Mcliola 
caynellioB)  which  not  only  clogs  up  the  breathing  pores  of 
the  leaves  and  renders  them  incapable  of  performing  their 
normal  functions,  but  also  forms  a  black  coating  over  the 
fruit  which  necessitates  thorough  washing  before  the  fruit 
can  be  packed  for  market.  This  washing  is  often  of  neces- 
sity so  severe  as  to  cause  abrasions  in  the  skin  and  a  con- 
siderable increase  in  the  amount  of  decay  during  transit 
to  market. 

The  size  of  the  adult  scale  will  average  about  one-seventh 
of  an  inch  in  length  and  not  quite  as  broad.  It  may  be  dis- 
tinguished from  closely  related  species  by  a  plainly  outlined 
letter  H  on  the  back  of  the  full  grown  females.  The  color 
of  the  mature  female  is  usually  very  dark,  often  jet  black. 
The  male  scale  is  minute  and  is  very  seldom  seen.  When 
mature  the  male  emerges  from  its  pupal  case  as  a  winged 
insect. 


408  Citrus  Fruits 

The  life  history  of  the  hhick  scale  varies  in  diflferent  sections, 
but  in  general  it  is  about  as  follows  : 

Eggs  are  produced  most  abundantly  in  May,  June,  and  part 
of  July,  the  average  number  found  under  each  scale  being 
about  eighteen  hundred.  In  about  twenty  days  the  eggs 
hatch.  At  the  end  of  a  day  or  two  the  young  insects  make 
their  way  out  from  under  the  protecting  mother  scale,  and 
crawl  around  for  two  or  three  days  before  settling  down, 
the  leaves  and  tender  twigs  offering  the  most  suitalile  feeding 
ground.  Unlike  the  armored  scales,  the  black  scale  is,  up 
to  a  certain  age,  able  to  withdraw  its  sucking  mouth-parts 
from  the  tissues  and  move  to  more  favorable  pasturage. 
This  accounts  for  the  fact  that  only  a  few  mature  individuals 
are  seen  on  the  leaves,  while  such  large  numbers  are  found 
on  the  branches. 

The  yellowish  half  grown  females  are  most  common  from 
about  the  middle  of  September  to  the  middle  of  December, 
while  during  the  spring  and  early  summer  months  the  dark 
adult  scales  are  most  abundant.  Although  there  seems  to  be 
but  one  generation  of  the  black  scale  during  the  year,  it  is  not 
uncommon  along  the  coast  to  find  all  stages  at  one  time. 
It  is  this  irregularity  in  the  appearance  of  the  young  scales 
that  makes  the  problem  of  control  so  difficult.  The  insect 
is  naturally  most  susceptible  to  any  destructive  influence 
during  the  two  or  three  days  when  it  is  crawling  around 
searching  for  a  suitable  place  to  feed.  The  hot  dry  air  of 
the  interior  valleys  kills  them  off  in  large  numbers  and  they 
are  not  able  to  establish  themselves  so  readily  as  in  the  coast 
sections. 

The  young  insects  may  readily  be  seen  crawling  about  over 
the  leaves  and  stems,  but  a  little  observation  will  show  that 
their  powers  of  locomotion  are  very  limited  ;  they  are  not 
able  to  crawl  from  one  tree  to  another  over  the  rough  ground 


Citrus  Insects  and  their  Control  409 

and  must  depend  upon  some  other  agency  to  carry  them 
any  considerable  distance.  Probably  the  most  common 
agents  for  their  dispersal  are  the  ladybird  beetles.  These 
and  other  insects  are  often  found  with  one  or  more  young 
scales  on  their  backs,  and  when  the  beetles  fly  to  other  trees, 
the  scales  are  carried  along  to  start  new  infestations.  Birds 
are  probably  responsible  for  transporting  young  scale 
insects  long  distances,  as  the  latter  have  ample  opportunity 
to  crawl  upon  the  bodies  of  birds  wliich  are  roosting  in  the 
trees  or  resting  between  flights.  Man,  however,  has  been 
mostly  responsible  for  the  wide  distribution  of  the  black 
and  similar  scales,  especially  by  the  shipment  of  promiscuous 
lots  of  nursery  stock  from  one  country,  or  one  section  to 
another.  In  the  orchard  the  yoimg  scale  is  very  liable  to  be 
distributed  during  the  ordinary  operations  of  cultivation,  prun- 
ing, picking,  and  hauling  to  market.  In  some  packing-houses 
the  precaution  is  taken  of  fumigating  all  lug-boxes  as  they 
are  emptied.  They  are  loaded  directly  into  the  wagons 
from  the  fumigating  room,  to  be  taken  back  to  the  orchard. 
In  this  way  the  danger  of  introducing  scale  into  a  clean  or- 
chard by  means  of  lug-boxes  is  reduced  to  a  minimum. 

There  are  several  natural  enemies  of  the  black  scale  in 
California.  Among  these,  the  most  important  is  the  parasite, 
ScufcUista  cyanca,  which  was  introduced  from  South  Africa 
in  1900  and  is  now  found  in  most  of  the  districts  where  black 
scale  abounds.  The  Scutellista  is  an  egg  parasite  and  the 
larvpe  feed  only  on  the  eggs  which  are  deposited  by  the  mature 
black  scale.  In  some  cases  all  the  eggs  under  one  scale 
may  be  consumed,  but  in  other  cases  the  parasites  come  to 
maturity  mth  a  greater  or  less  number  of  eggs  untouched. 
Even  if  the  eggs  are  completely  destroyed  in  the  parasitized 
scales,  there  are  usually  a  sufficient  number  of  female  scales 
which  are  not  parasitized  to  carry  on  the  Infestation.     While 


410  Citrus  Fruits 

the  Scutellista  aids  materially  in  reducing  the  numbers  of 
the  scales,  it  cannot  be  depended  on  alone  for  the  effective 
control  of  the  pest. 

Another  egg  parasite,  Tomocera  caJifornica,  is  found  in 
some  sections  but  is  not  nearly  so  effective  as  the  preceding. 
There  are  at  least  four  ladybird  beetles  as  well  as  an  internal 
parasite  of  the  male  insect  which  also  prey  upon  the  black  scale. 

Where  only  a  few  trees  around  the  house  are  infested  or 
only  young  trees  require  treatment,  spraying  with  distillate 
emulsion  or  kerosene  emulsion  is  recommended.  The  emul- 
sion is  made  as  follows  : 


Kerosene 1  gallon 

Soap  (laundry) h  pound 

Water 15  gallons 


The  soap  should  first  be  dissolved  in  about  a  gallon  of  hot 
water,  and  while  still  hot,  add  the  kerosene,  away  from  the 
fire.  The  mixture  may  then  be  emulsified  by  churning  it  back 
and  forth  for  several  minutes  until  it  becomes  of  the  consist- 
ency of  cream,  when  it  is  diluted  to  make  the  sixteen  gallons. 
The  oil  should  be  thoroughly  emulsified  before  being  used, 
as  free  oil  in  the  mixture  is  apt  to  cause  serious  injury  to 
the  bark  of  young  trees.  Where  the  soil  is  sandy  the  con- 
centration of  the  spray  material  which  runs  down  the 
trunks  and  reaches  the  soil  may  cause  injury  at  the  collar. 
In  such  cases  the  oil-saturated  soil  should  be  removed 
from  about  the  collar  and  replaced  by  a  few  handfuls  of 
fresh  soil.  This  should  be  done  three  or  four  hours  after 
the  spray  has  been  applied. 

Fumigation  is  usually  more  effective,  however,  in  control- 
ling l)lack  scale,  as  the  gas  penetrates  to  all  parts  of  the  tree 
and  the  fumigation  properly  done  kills  both  the  mature  and 
half  grown  scales. 


Citrus  Insecfs  and  their  Cuiifrol  411 

The  Red  or  Orange  Scale  {Chrysomphalm  aurantii) 

The  red  scale  is  found  along  with  the  black  scale  in  the 
southern  coast  counties,  where  it  is  a  serious  enemy  of  citrus 


Fic.  140.  —  The  red  scale  on  orange. 

trees.  It  takes  first  rank  as  a  pest  in  San  Bernardino  and 
Riverside  counties,  while  in  Orange  and  Los  Angeles  counties 
it  takes  second  place.  It  was  found  in  California  in  1878, 
and  the  origin  of  that  infestation  was  traced  to  Australia,  al- 


412  Citrus  Fruits 

thou<i;li  China  is  usually  regarded  as  its  native  home.  It 
occurs  in  nearly  all  tropical  and  semi-tropical  countries  on  a 
large  number  of  plants,  hut  is  especially  a  pest  on  citrus 
trees.  Unlike  the  black  scale,  it  does  not  produce  honey- 
dew.  The  injury  to  the  tree  is  due  either  to  the  loss  of  sap 
or  to  the  poisonous  effects  upon  the  cells  of  the  tissues 
attacked.  While  the  black  scale  is  never  known  to  kill 
a  tree  upon  which  it  is  feeding,  the  red  scale  quite  commonly 
aifects  its  host  plant  very  seriously  if  not  fatally.  It  also 
settles  upon  the  fruit,  marring  its  appearance  and  market 
qualities.  The  life  history  differs  from  that  of  the  black 
scale  in  the  fact  that  the  mature  female  does  not  produce 
eggs  but  gives  birth  to  living  young.  These  young  scales 
are  minute,  but  may  be  observed  from  June  to  September  or 
later  as  yellowish  mites  crawling  on  the  leaves,  stems,  or 
fruit.  They  do  not  migrate  far  from  the  parent  scale  unless 
the  food  supply  is  scarce  or  the  feeding  surface  dry  and  hard, 
in  which  cas'e  they  may  travel  several  feet.  The  scaly  cover- 
ing which  the  young  insect  ])egins  to  form  over  itself  as  soon 
as  it  is  settled  is  simply  for  protection,  and  is  not  a  part  of 
the  body,  as  in  the  case  of  the  half  grown  black  scale.  It 
consists  of  a  mass  of  light  cottony  threads  secreted  by  the 
young  scale ;  later  this  is  enlarged  by  the  two  cast-off  skins 
of  the  growing  larvae.  lender  this  protection,  they  con- 
tinue to  feed  until  mature,  which  requires  from  two  and  a  half 
to  three  and  a  half  months.  The  mature  female  scale  is 
reddish  in  outward  appearance  and  about  the  size  of  the 
head  of  an  ordinary  pin.  The  mature  male  scale  is  smaller 
and  more  elongated  than  the  female.  The  male  sheds  its 
skin  four  times  and  emerges  as  a  winged  insect  in  from  one 
and  a  half  to  two  months. 

Although  each  female  produces  but  from  forty  to  eighty 
young,  the  fact   that  in  southern  (California  there   are  four 


Fig.  141.  —  Work  of  red  .scale  on  orange 
413 


414  Citrus  Fruits 

generations  during  the  season  accounts  for  tlieir  rapid  in- 
crease. The  same  agents  responsible  for  the  spread  of  the 
black  scale  also  disseminate  the  red  scale. 

The  internal  parasites  of  the  red  scale  do  not  seem  to  be  at 
all  effective  in  reducing  their  numbers,  as  only  a  small  per- 
centage of  the  scales  are  parasitized.  Several  species  of  the 
ladybird  beetles  are  commonly  found  attacking  the  red 
scale,  but  are  not  of  much  assistance  in  their  control.  Fumi- 
gation according  to  the  schedule  given  in  Chapter  XXIII 
is  the  most  effective  remedy. 

Yelloio  Scale  (Ckrysomphalus  aurantii  var.  citrinus) 

The  yellow  scale  is  but  a  variety  of  the  red  scale,  and  is 
identically  the  same  in  structure.  It  is  somewhat  yellow  in 
color,  although  the  color  becomes  much  darker  after  the 
insect  dies,  when  it  is  more  difficult  to  distinguish  from 
the  red  scale.  The  distribution  is  about  the  same  as  that  of 
the  red  except  in  the  Sacramento  Valley,  where  the  yellow 
scale  seems  to  occur  exclusively. 

The  feeding  habit  of  this  scale  differs  from  that  of  the  red 
as  its  attacks  are  almost  wholly  restricted  to  the  leaves  and 
fruit.  The  seriousness  of  the  injury  is  therefore  much  less 
and  the  health  of  the  trees  is  not  so  seriously  injured. 

The  life  history  agrees  with  that  of  the  red  scale.  There 
is  an  internal  parasite  which  sometimes  kills  25  per  cent  of 
the  scale,  but  fumigation  must  be  relied  upon  for  its  com- 
plete control. 

The  Purple  Scale  {Lepidosaphes  heckii) 

The  date  of  introduction  of  the  purple  scale  into  California 
seems  to  have  been  either  1888  or  1889,  when  two  carloads 
of  orange  trees  were  received  from  Florida  and  planted  in 


Citrus  Insects  and  their  Control  415 

Los  Angeles  and  San  Diego  counties  wnthout  disinfection. 
It  now  occurs  in  San  Diego,  Los  Angeles,  Orange,  Ventura, 
and  Santa  Barbara  counties,  and  a  strict  inspection  is  being 
maintained  in  the  more  inland  counties  to  prevent  its  intro- 
duction. The  purple  scale  attacks  all  parts  of  the  tree  as  well 
as  the  fruit,  upon  which  they  attach  themselves  so  firmly 
that  the  ordinary  washing  is  of  little  avail  in  removing  them. 
They  also  cause  the  fruit  to  appear  spotted  in  ripening,  a 
green  color  persisting  around  the  scales.  Whole  trees  are  sel- 
dom if  ever  killed  by  this  scale,  although  the  lower  branches 
and  often  one  whole  side  of  the  tree  may  be  fatally  affected. 

Eggs  of  the  purple  scale  are  most  commonly  found  during 
the  spring  and  early  summer,  although  all  stages  may  occur 
in  the  orchard  at  other  seasons.  The  female  produces 
from  thirty  to  forty  eggs,  which  hatch  in  about  eighteen  days 
during  the  summer  months.  The  young  remain  under  the 
protection  of  the  mother  for  a  short  time,  after  which  they 
make  their  way  out  and  migrate  in  search  of  a  place  to  feed. 
After  they  have  once  settled  down  and  formed  the  protect- 
ing scale  over  their  bodies  the  females  are  stationary  dur- 
ing their  entire  existence.  The  mature  female  scales  are 
elongated,  and  shaped  somewhat  like  an  oyster  shell,  the  color 
varying  from  a  dark  brown  to  purplish.  The  male  scale  is 
much  smaller  and  narrower.  The  average  length  of  time 
from  the  egg  to  maturity  is  about  two  and  one-half  months 
for  the  male  and  three  months  for  the  female.  After  the 
production  of  eggs,  the  female  soon  dies. 

During  the  ordinary  season,  there  are  from  three  to  four 
generations.  The  young  seem  to  be  more  able  to  adapt  them- 
selves to  unfavorable  feeding  conditions  than  either  the  red 
or  the  black  scales,  and  the  percentage  which  become  estab- 
lished is  much  greater. 

Several  species  of  ladybird  beetles  prey  upon  the  purple 


41G 


Cifnift  Frin'i.9 


m 

«;■■ 

Fig.  142.  —  Tho  purple  scale.      (Enlarged.) 


scale,  but  only  one  internal  parasite  has  so  far  been  reared. 
This  parasite  is  not  very  widely  distributed  and  is  only 


Citrus  Insects  and  their  Control 


417 


partially  effective  wherever  it  is  found.  In  orchards  where 
the  red,  black,  and  purple  scales  occur  together,  fumigation  is 
mainly  directed  against  the  purple ;  if  it  is  killed,  the  dosage 
is  usually  fatal  to  the  other  two. 

Cottony  Cushion  Scale  (Iccrya  purchasi) 

The  account  of  the  introduction,  spread,  and  final  control 
of  the  cottony  cushion  scale  forms  one  of  the  most  interesting 


chapters  in  the  history  of  California  horticulture.  Having 
been  introduced  from  Australia  in  1868  (see  Chapter  I) 
it  spread  so  rapidly  tluring  the  next  twenty  years  that  its 
ravages  proved  a  very  serious  menace  to  the  citrus  industry 
of  the  southern  part  of  the  state.  The  Australian  ladybird 
beetle  which  was  introduced  into  California  from  Australia 
in  1889  for  the  purpose  of  controlling  this  scale  was  so  success- 
ful, to  all  appearances,  that  except  for  occasional  outbreaks 
it  ceased  to  be  considered  as  a  serious  citrus  pest,  and  fumi- 
gation or  other  measures  of  repression  are  no  longer  necessary. 
2e 


418  Citrus  Fruits 

The  mature  scale  is  very  easily  distinguished  from  other 
scales.  When  mature,  they  are  about  one-fourth  of  an  inch 
long  and  consist  of  the  red  or  yellowish  body  and  a  large 
fluted  cottony  white  mass  which  serves  as  the  egg-sac. 
From  five  to  eight  hundred  eggs  are  produced  by  each  female, 
May  and  June  being  the  season  of  greatest  production. 
These  hatch  in  about  ten  days  in  summer,  but  a  longer  period 
is  required  in  winter.  The  young  scales  are  very  active,  and 
feed  at  first  largely  upon  leaves  but  later  seem  to  prefer  the 
twigs  and  branches.  The  females  are  able  to  move  about 
during  most  of  their  life,  but  become  stationary  as  soon  as 
the  egg-sac  is  formed.  The  time  required  for  development 
from  egg  to  adult  varies  considerably  even  during  the  same 
season ;  the  average,  however,  is  about  three  and  a  half 
months.  There  are  at  least  three  generations  in  southern 
California,  and  during  the  summer  months  they  increase 
very  rapidly  if  not  held  in  check  by  their  natural  enemies. 
The  cottony  cushion  scale  produces  a  large  quantity  of 
honey-dew,  on  which  the  sooty  mold  fungus  grows  readily. 

Soft  Broum  Scale  {Coccus  hesperidum) 

The  soft  brown  scale  is  widely  distributed  over  the  earth 
and  has  a  large  number  of  food  plants  other  than  citrus.  Its 
injury  to  citrus  trees  is  due  largely  to  the  exudation  of  honey- 
dew,  and  the  accompanying  growth  of  the  sooty  mold  fungus. 
It  is  only  occasionally  injurious,  and  seldom  infests  an  entire 
orchard,  being  usually  held  in  check  by  several  internal 
parasites.  This  scale  is  usually  accompanied  by  a  great 
number  of  ants  which  feed  upon  the  honey-dew. 

The  young  scales  are  produced  alive  during  the  summer 
months  and  settle  down  soon  after  leaving  the  protection 
of  the  mother.  They  either  remain  fixed  from  that  time  or 
occasionally  move  about  imtil  they  are  half  grown.     There 


Cifrufi  Insects  and  their  Control  419 

may  l)e  several  generations  in  a  season,  as  they  require  from 
sixty-five  to  ninety  clays  to  mature  in  summer.  The  scales 
often  crowd  so  thickly  on  the  leaves  or  along  the  stems  as 
to  overlap  each  other.  The  body  of  the  mature  female  is 
oval,  flat,  and  soft,  varying  in  color  from  a  dark  straw  yellow 
to  brown,  often  with  deeper  markings.  The  male  scales 
are  much  smaller  and  lighter  in  color,  the  mature  form 
emerging  as  a  winged  insect. 

As  stated  above,  this  insect  is  seldom  serious,  })ut  occasion- 
ally it  happens  that  the  parasites  do  not  effectively  control  it, 
and  it  becomes  necessary  to  fumigate  or  spray. 

Citricola  or  Soft  Gray  Scale  {Coccus  citricola) 

During  the  past  five  years  a  scale  supposed  to  be  a  variety 
of  the  soft  brown  has  caused  much  damage  to  citrus  trees 
both  in  the  coast  country  and  interior  valleys.  Recently 
the  insect  has  been  described  as  a  distinct  species.^ 

The  citricola  scale  excretes  large  amounts  of  honey-dew 
which  becomes  covered  with  sooty  mold,  necessitating  the 
washing  of  the  oranges.  The  presence  of  the  scale  is  usually 
first  noticed  in  July  and  August,  when  the  sooty  mold  is 
forming.  In  the  spring  the  adult  females  can  be  observed 
on  the  smaller  twigs  and  branches,  often  being  so  numerous 
as  to  overlap  each  other  and  cause  the  twig  to  appear  twice 
as  large  in  diameter  as  ordinarily.  This  scale  is  not  fatal 
to  the  tree,  but  saps  its  vitality  and  results  in  small  crops  of 
undersized  sooty  fruit. 

The  adult  female  is  grayish  in  color,  usually  about  one- 
fourth  inch  long  and  about  three-sixteenths  wide,  and  elongates 
oval  in  shape.  Eggs  are  laid  during  May  and  June  and 
hatch  immediately.  In  fact,  in  some  cases  the  eggs  hatch 
before  they  are  laid,  and  the  young  are  born  alive.     The 

^  Roy  E.  Campbell,  Entomological  News,  June,  1914. 


420  Ciirus  Fruits 

parasites  of  the  citricola  scale  do  not  control  it  effectively, 
and  it  has  increased  in  the  citrus  orchards  at  an  alarming 
rate.  The  chief  method  of  control  is  by  fumigation,  which 
is  done  in  July  and  August  at  the  time  when  the  greatest 
percentage  of  young  scales  are  susceptible  to  the  gas. 

Hemispherical  Scale  {Saissetia  hcmisphcerica) 

Although  this  scale  is  not  a  serious  pest  in  citrus  orchards, 
it  sometimes  becomes  abundant  on  trees  growing  near  the 
coast.  It  attacks  the  twigs  and  leaves,  upon  which  it  quite 
commonly  settles  along  the  very  edge.  It  may  be  distin- 
guished from  the  black  scale  by  the  absence  of  the  letter  H 
on  the  back,  its  regular  oval  shape,  and  polished  brown 
surface  without  markings.  The  same  control  measures 
used  for  the  black  scale  are  also  efficacious  for  this  species. 

Greedy  Scale  {As  pi  di  of  us  rapax) 

This  species  is  of  only  minor  importance  as  a  citrus  pest 
but  sometimes  attacks  the  twigs  and  may  be  found  upon 
fruit  remaining  upon  the  trees  from  the  previous  season. 
As  its  name  implies,  it  seems  to  have  no  choice  of  host  plants, 
but  thrives  on  both  wild  and  cultivated  shrubs  or  trees.  The 
mature  scale  is  gray  or  almost  white  and  somewhat  trans- 
lucent, showing  the  yellow  l)ody  of  the  insect  beneath.  It 
is  ordinarily  associated  with  other  species  on  citrus  trees 
and  remedial  measures  directed  against  this  scale  alone  are 
seldom  if  ever  necessary. 

Oleander  Scale  (Aspidiotus  hederoe) 

The  oleander  scale  is  another  species  which  only  occasion- 
ally attacks  citrus  trees.  It  sometimes  appears  on  lemons, 
usually  on  tree-ripe  fruit,  and  the  common  name  of  "  lemon 


Cifnis  luscct.s'  and  their  Control  421 

peel  scale"  liiis  heeii  applied  to  it.  Altliotigh  its  normal 
color  varies  from  light  to  dark  gray,  it  may  assume  a  reddish 
tinge  when  found  on  lemons  and  may  then  be  mistaken  for 
the  red  scale. 

Citrus  Mealy  Bug  {Pseudocoeeus  citri) 

The  mealy  bug  does  not  have  to  be  reckoned  with  as  a 
continuous  pest  in  California  citrus  orchards.  When  climatic 
and  other  conditions  are  favorable,  it  becomes  a  very  serious 
citrus  insect  and  is  quite  difficult  to  control.  It  is  found  in 
all  the  citrus  regions  of  the  state,  but  has  been  particidarly 
troublesome  in  Ventura  and  San  Diego  counties.  It  not 
only  attacks  the  leaves  and  liranches,  but  seems  to  be  espe- 
cially fond  of  the  fruit,  often  collecting  in  masses  on  both 
oranges  and  lemons.  When  concealed  in  the  navel  of  the 
orange  or  aroimd  the  stems  of  lemons,  the  insects  may  escape 
detection  and  continue  to  breed  while  the  fruit  is  in  storage 
or  on  the  way  to  market. 

The  honey-dew  excreted  ])y  the  mealy  bug  is  very  sticky 
and  makes  the  task  of  cleaning  the  fruit  exceedingly  difficult. 

From  three  hundred  and  fifty  to  four  hundred  eggs  are 
deposited,  mostly  during  the  fall  and  early  winter,  in  a  mass 
of  loose,  cottony  fibers,  excreted  at  the  time  by  the  female. 
The  eggs  hatch  in  eight  to  ten  days  during  the  summer  months, 
and  in  about  sixteen  days  during  the  winter.  The  young  in- 
sects move  about  actively,  the  distance  depending  upon  the 
amount  and  condition  of  the  food  supply.  The  females 
continue  to  move  al)out  during  their  lifetime,  but  the  males 
form  a  cocoon  and  go  through  a  stage  of  transformation  and 
emerge  in  six  weeks  as  two-winged  insects,  at  which  time  the 
females  are  about  half  grown.  The  females  require  about 
two  and  a  half  months  to  develop,  often  commencing  to 
produce  eggs  before  they  reach  full  size.     The  full  grown 


422 


Cifriis  Fniiff 


mealy  bug^s  are  about  one-fourth  of  an  inch  in  length  and  con- 
spicuously clothed  wnth  a  white,  mealy  excretion.  They 
have  a  border  of  short  appendages  around  their  bodies,  the 

posterior  appendages 
being  but  little  longer 
than  the  lateral.  They 
have  the  habit  of 
settling  down  in  pro- 
tected places  such  as 
the  leases  of  the  leaves 
and  fruit  stalks,  often 
causing  the  leaves  and 
young  fruit  to  drop 
prematurely. 

The  mealy  bug 
passes  the  winter  in 
the  egg  stage,  but  on 
account  of  the  uneven 
hatching  during  the 
warm  weather  of 
southern  California, 
usually  all  stages  may 
be  found  during  the 
winter  season. 

On  account  of  the 
habit  which  the  mealy 
bugs  have  of  secreting 
themselves  in  pro- 
tected places,  control 
Fig.  144.  —  Citrus  mealy  hug.  measures  by  means  of 

spraying  are  difficult.  They  seem  to  be  quite  resistant 
to  fumigation,  and  unless  scale  insects  are  also  present 
in  sufficient    numbers    to    require    fumigation,  such  treat- 


Citrus  Insects-  and  their  Control  423 

ment  is  not  recommended.  The  greatest  success  has  been 
obtained  by  the  use  of  distillate  emulsion  spray,  ten  to 
fifteen  gallons  being  applied  to  an  ordinary  tree.  The 
emulsion  consists  of  four  gallons  of  distillate  oil,  one  gallon 
of  liquid  soap  to  two  hundred  gallons  of  water.  If  the  in- 
sects are  abundant,  it  may  be  necessary  to  spray  two  or 
three  times.  The  best  time  for  application  is  during  the 
winter  when  there  are  large  numbers  of  eg^  mjusses,  or  in 
the  spring  when  the  young  have  been  hatched. 

There  are  several  predaceous  insects  as  well  as  parasites 
which  assist  in  controlling  the  mealy  bug ;  these  include 
different  species  of  ladybird  beetles,  lace-wing  flies,  and 
internal  parasites. 

Citrus  Red  Spider  (Tcfranyehus  mytilaspidis)  and  Si.v  Spotted 
Mite  (T.  sexmaculatus) 

There  are  two  species  of  red  spiders  which  attack  citrus 
trees  in  California.  They  occur  throughout  the  citrus  dis- 
tricts and  rank  second  to  scale  insects  as  citrus  pests.  They 
injure  the  plant  by  sucking  the  juices  from  the  tissues, 
giving  a  characteristic  mottled  and  sickly  appearance  to 
the  leaves.  The  green  fruit  also  is  attacked,  and  an  objec- 
tionable pale  silvery  color  produced.  Red  spiders  also 
sometimes  injure  lemons  in  packing-houses  while  the  lemons 
are  in  storage. 

Since  the  citrus  red  spider  is  the  one  usually  responsible 
for  injury  to  citrus  trees,  that  species  is  the  one  which  will 
be  discussed  here.  The  common  red  spider  or  six  spotted 
mite  does  not  limit  itself  to  citrus  as  a  food  plant,  although 
in  San  Diego  County  it  is  sometimes  a  more  important 
lemon  pest  than  the  other  species. 

The  citrus  red  spider  was  introduced  from  Florida  on 
nursery  stock  about  1890  and  has  been  a  serious  pest  since 


424  Cifni.s-  Fnu'h 

1895.  It  is  very  ininutr,  red  in  eolor,  und  often  becomes  so 
abundant  on  a  leaf  as  to  give  it  a  reddish  hue  also.  The  red 
eggs  are  placed  separately  on  the  leaves,  and  are  ele\ated 
upon  short  stalks  held  in  place  by  radiating  guy  threads 
fastened  to  the  surface  of  the  leaf.  The  number  deposited 
by  each  female  will  average  about  thirty.  During  the 
month  of  May  and  the  summer  months,  about  ten  days  are 
required  for  hatching,  although  it  may  take  three  weeks  in 
the  cooler  seasons.  The  young  begin  to  feed  immediately 
and  grow  rapidly,  only  twelve  days  being  required  to  reach 
maturity  and  begin  egg-laying. 

Sulfur  is  the  universal  remedy  for  red  spider.  It  was 
first  applied  in  the  dry  powdered  form,  dusted  over  the  trees 
either  with  a  small  bellows  or  a  power  blower,  preferably 
when  the  foliage  was  damp.  Lime-sulfur  sprays  have  recently 
met  with  great  favor  and  are  being  extensively  used.  Natural 
enemies,  such  as  predaceous  beetles  and  the  lace-wang  flies, 
assist  materially  in  reducing  the  damage  due  to  red  spider. 
The  commercial  lime-sulfur  preparations  are  commonly 
used,  one  gallon  to  thirty-five  gallons  of  water  being  recom- 
mended. About  six  or  seven  gallons  of  the  solution  are 
required  for  the  ordinary  tree,  making  the  cost  about  fifteen 
cents,  consideral^ly  less  than  the  cost  of  fumigation. 

Silver  Mite   (Eriophyes  oleivorus) 

The  silver  mite  is  not  a  true  insect  but  belongs  to  the  same 
class  as  the  red  spider.  It  was  introduced  from  Florida  into 
San  Diego  County  in  1889  and  its  ravages  have  been  restricted 
to  a  section  of  that  county.  The  mite  attacks  the  bark, 
foliage,  and  fruit,  producing  the  greatest  injury  to  the 
fruit.  Green  lemons  if  attacked  take  on  a  silvery  appear- 
ance, due  to  the  extraction  of  the  oil  and  green  coloring 
matter  from  the  cells  of  the  rind.     On  oranges  it  produces 


Citrus  Insects  and  their  Control  425 

a  russet  color  of  tlie  fruit,  hence  it  is  sometimes  known  us 
the  rust  mite. 

The  eggs  of  the  silver  mite  are  deposited  singly  or  in  small 
clusters  on  the  leaves  or  fruit  and  hatch  in  from  five  to 
fourteen  days,  depending  upon  the  season.  The  young 
mites  grow  rapidly,  only  eight  to  ten  days  being  required  to 
reach  maturity,  and  in  the  course  of  the  season  they  may 
become  very  abundant.  The  adults  are  scarcely  visible 
to  the  naked  eye,  but  their  presence  is  indicated  by  the 
characteristic  silvery  color  produced  on  the  lemons  as  well 
as  on  the  leaves.  Such  fruit  is  either  thrown  out  as  culls 
or  utilized  in  making  by-products.  The  control  measures 
are  the  same  as  for  the  red  spider. 

Ornnrjt'    Thrip.i   (Eitfhrips  citri) 

Thrips  are  very  common  insects  in  nearly  all  kinds  of 
flowers,  including  citrus.  Blossoms  shaken  over  the  hand 
will  generally  dislodge  a  number  of  both  yoimg  and  adults ; 
the  latter,  being  very  active,  either  jump  or  fly  away.  Thrips 
which  occur  in  flowers,  however,  do  not  usually  belong  to 
the  above  species,  as  there  are  numerous  kinds  which  do 
comparatively  little  damage.  The  true  orange  thrips  are  most 
abundant  in  Arizona  and  in  the  San  Joaquin  citrus  district, 
but  are  also  occasionally  injurious  in  the  Redlands  district. 

The  presence  of  the  thrips  is  usually  e\'idenced  by  their 
work  upon  the  young  leaves,  which  are  commonly  distorted 
in  growth  and  leathery.  On  the  fruit  they  produce  scars 
which  may  form  regular  rings  around  the  stem  end,  or  appear 
in  irregular  spots  over  the  surface.  The  mouth-parts  of  the 
thrips  are  intermediate  between  the  sucking  and  biting 
insects  and  consist  of  a  chafing  or  rasping  rather  than  a  biting 
organ,  which  accounts  for  the  scars  produced  upon  the  leaves 
and  fruit.     Although  not  injuring  the  edible  qualities  of  the 


42() 


Citrus  Fruits 


oranges,  sucli  scars  affect  the  market  \a,\uv  hy  placing  the 
fruit  in  poorer  grades. 

The  adult  thrips  hibernate  over  winter  in  protected  places 
and  appear  about  the  middle  of  April,  feeding  upon  the  ten- 


due  to  citrus  thrip; 


der  leaves.  The  eggs  are  produced  throughout  the  summer 
months  and  hatch  in  six  to  ten  days  after  being  deposited. 
The  young  are  very  active  and  resemble  the  mature  forms, 
except  that  they  are  much  lighter  in  color  and  without 
wings.     It  has  been  estimated  that  there  are  from  eight  to 


Citrus  Insects  and  their  Control  427 

ten  generations  a  year  in  the  San  Joaquin  Valley,  about 
twenty  days  being  required  for  development  from  egg  to 
adult,  and  about  twenty-three  days  the  average  length  of 
life  after  reaching  maturity. 

The  most  effective  remedy  for  thrips  seems  to  be  spraying. 
The  formula  recoinmended  by  the  U.  S.  D.  A.  Bureau  of 
Entomology  is  as  follows  : 

Commercial  lime  sulfur  (33°)        2^  gal. 

Black  leaf  extract  .  .  .  2  gals,  of  2f%  or  14  fluid  oz.  of  40% 
Water 200  gal. 

It  is  necessary  to  use  a  very  strong  pressure,  175  to  200 
pounds,  in  applying  the  spray  so  that  all  parts  of  the  tree  shall 
be  reached.  The  first  application  should  be  made  as  soon 
as  the  petals  have  fallen ;  a  second  and  third  spraying  is 
advisable  at  intervals  of  about  ten  days. 

While  spraying  for  thrips  has  been  practiced  on  a  large 
scale,  it  is  a  fact  that  at  present  but  little  spraying  is  done. 
Inasmuch  as  the  thrips  is  severe  only  in  occasional  years, 
most  growers  prefer  to  take  the  risk  rather  than  to  go  to 
the  expense  of  spraying. 

Melon  Aphis  or   Plant  Louse   (Aphis  gossypii) 

This  species  of  plant  louse  is  very  common  throughout 
California  on  melons,  gourds,  and  weeds,  and  at  times  becomes 
abundant  on  citrus  trees,  especially  in  early  spring.  They 
attack  the  tender  young  growth  and  under  sides  of  the  leaves, 
causing  the  latter  to  curl.  Such  infestations  are  rarely  very 
extensive,  the  injury  being  usually  confined  to  a  few  scattered 
branches.  Unfavorable  weather,  ladybird  beetles,  and  other 
natural  enemies  ordinarily  keep  the  numbers  of  plant  lice 
reduced.  In  case  they  are  doing  much  damage  to  young 
nursery  stock,  however,  a  spray  of  nicotine  extract  or  weak 
soap  solution  will  be  found  effective. 


428  Citnifi  FruiU 


Orcnufc   Torfri.r  (Tnrfri.r  rifrfina) 

The  orange  tortrix  iittitcks  a.  groat  variety  of  plants,  both 
wild  and  cultivated,  feeding  mostly  npon  the  leaves,  which  it 
fastens  together  by  silken  threads.  It  was  first  described 
in  1889,  and  has  lieen  reported  occasionally  as  injuring  various 
plants,  including  the  fruit  of  orange  trees.  In  1910,  its  injury 
to  oranges  in  southern  California,  especially  in  Los  Angeles 
County,  caused  the  growers  no  little  alarm,  as  high  as  ten  per 
cent  of  the  fruit  l)eing  found  wormy  in  some  of  the  packing- 
houses. The  damage  is  done  by  the  larva  or  small  worm 
which  burrows  its  way  into  the  fruit,  seldom  going  deeper 
than  the  rind,  however.  These  holes  in  the  rind  not  only 
cause  the  fruit  to  be  graded  as  culls  but  also  pro\ide  an 
entrance  for  the  germs  of  decay. 

The  eggs  are  deposited  on  leaves  or  fruit  in  small  masses 
of  from  ten  to  thirty-five  eggs,  overlapping  each  other  like 
fish  scales.  They  hatch  in  about  twelve  days  and  the  larvae 
feed  at  first  upon  the  surface  of  the  fruit  or  on  the  leaves  but 
iater  burrow  into  the  rind,  where  they  remain  until  full  grown. 
At  this  time  they  are  about  half  an  inch  in  length.  They 
form  a  chrysalis  either  in  the  burrow  or  in  a  protected  place 
outside,  and  at  the  end  of  ten  days  emerge  as  yellowish  gray 
moths,  less  than  half  an  inch  long.  According  to  observations 
which  have  been  made  in  the  orchards,  there  are  probably 
three  generations  of  the  tortrix  in  southern  California. 

So  far  no  effective  method  of  control  by  insecticides  has 
been  worked  out.  Fortunately  the  serious  outbreaks  are 
spasmodic,  occurring  only  in  occasional  years.  Often  they 
are  confined  to  small  localities  or  even  particular  groves. 
Perhaps  the  most  practical^le  remedy  is  to  destroy  the  fallen 
fruit  before  the  larvre  have  emerged,  and  also  to  destroy  the 
wormy  culls  from  the  packing-houses. 


Citrus  In,s'pcts  and  ihclr  Control 


429 


Fuller's  Rose  Beetle  (Aramigus  fulleri) 

The  injury  done  by  Fuller's  rose  beetle  is 
most  serious  on  young  trees  and  young,  ten- 
der foliage  of  larger  trees.  The  adult  beetles 
live  on  the  foliage,  feeding  mostly  at  night, 
while  the  larvje  or  grubs  feed  on  the  roots, 
so  that  both  stages  do  considerable  damage 
where  they  are  abundant.  The  beetle  is 
wingless,  grayish  brown  in  color,  and  about 
three-eighths  of  an  inch  in  length ;  the 
head  tapers  into  a  short  snout. 

Since  the  adults  are  unable  to  fly 


Fig.  146. —  Full- 
er's rose  beetle. 
(Enlarged.) 


they 

may  easily  be  pre- 
vented from  reach- 
ing the  foliage  of 
trees  by  bands  of 
cotton  or  tangle- 
foot placed  around 
the  trunks.  The 
band  of  cotton 
about  four  inches 
wide  is  wrapped 
around  the  trunk 
and  tied  tightly 
along  the  lower 
edge ;  the  upper 
half  is  then  pulled 
down  over  the 
lower  so  that  it 
flares  out  a  little 
from  the  trunk. 
This  remedy  is 
Fig.  147.  —  The  work  of  Fuller's  rose  beetle.        especially   effective 


430 


Citni.s  Fniitfi 


where  old  trees  have  their  tops  removed  for  top-working. 
In  such  cases  a  few  beetles  may  quickly  destroy  all  the  buds 
inserted  in  the  stump. 


Westerji  Tioelve-s potted  Cucumber  Beetle  (Diabrotica  soror) 

This  species  of  Diabrotica  is  liable  to  attack  the  leaves  and 
flowers  of  almost  any  kind  of  plant  which  it  happens  to  find. 

The  young  and  tender 
foliage  of  citrus  trees  is 
often  seriously  injured 
by  the  beetles  although 
orange  leaves  seem  to 
be  much  preferred  to 
those  of  the  lemon. 
The  beetles  appear  in 
such  numbers  at  certain 
seasons  that  control 
measures  must  be  used 
to  protect  young  plants 
from  their  attacks. 
During  the  early  morn- 
ing, while  they  are  in- 
active, the  beetles  are 
quite  easily  jarred  from 
the  trees  into  a  vessel  containing  kerosene  or  on  to  a  tarred 
screen.  Spraying  will  also  be  found  effective,  arsenate  of 
lead,  eight  pounds  to  two  hundred  gallons  of  water,  being 
recommended. 

Katydids  often  produce  scars  on  oranges  such  as  are 
shown  at  Fig.  148.  The  insects  eat  away  the  exterior  of  the 
rind  while  the  fruit  is  quite  small.  As  the  fruit  increases  in 
size  the  scars  enlarge. 


Fig.  148.- 


Scars  on  rind  of  orange  caused 
by  katydid. 


CHAPTER   XXIII 
INSECT  CONTROL   BY  FUMIGATION 

The  control  of  insects  by  fumigation  was  first  seriously 
considered  in  California  in  1886  when  the  cottony  cushion 
scale  was  ravaging  the  orchards  of  Los  Angeles  County. 
At  the  request  of  certain  citrus  growers,  E.  W.  Hilgard  of 
the  California  Experiment  Station  detailed  F.  W.  Morse 
of  the  University  of  California  to  carry  on  an  investigation 
looking  toward  the  control  of  the  scale  by  fumigation. 
Mr.  Morse  began  work  in  April,  1887,  and  soon  found 
that  hydrocyanic  acid  was  the  most  effective  of  any  of 
the  gases  experimented  with.  The  results  achieved  by 
Morse  attracted  the  attention  of  the  Los  Angeles  County 
Board  of  Horticultural  Commissioners,  who  offered  to 
pay  the  expenses  of  a  more  comprehensive  investigation. 
This  was  made  later  in  the  same  summer,  and  the  results 
published  as  bulletins  71  and  73  of  the  California  Experi- 
ment Station  dated  June  12  and  August  27,  respectively. 

It  then  became  known  that  D.  W.  Coquillett  had  dis- 
covered the  value  of  hydrocyanic  acid  for  fumigation  in 
the  fall  of  the  previous  year,  but  had  kept  the  fact  secret 
while  endeavoring  to  perfect  the  method  for  the  purpose 
of  securing  a  patent.  Later  Coquillett  accepted  an 
appointment  as  Spe'cial  Agent  for  the  Division  of  Ento- 
431 


432  Citrus  Fruits 

mology  of  the  U.  S.  I)ei)artineiit  of  Aii;riculture  and  con- 
tinuing his  experiments  with  fumigation  |)ul)hshe(l  a  series 
of  reports  on  the  subject  which  proved  of  great  vahie  to 
the  industry. 

About  the  year  1901,  a  much  cheaper  meth(jd  of  con- 


FiG.  149.  —  A  fumigation  demonstration. 

trolling  scale  by  spraying  with  distilhite  oil  was  intro- 
duced. It  was  soon  found,  however,  that  spraying  was 
much  less  effective  than  fumigation.  The  black  scale 
increased  to  an  alarming  extent,  and  the  thorough  wash- 
ing made  necessary  by  the  sooty  mold  caused  a  great 
increase  in  the  decay  in  transit.  As  soon  as  it  was  proven 
that  a  hirge  i)roportion  of  the  decay  in  transit  was  due 


Insect  Control  1)1/  Fnmiqntion  433 

primarily  to  the  presence  of  hlaek  scale  in  the  orchards, 
the  growers  took  a  renewed  interest  in  fumigation.  R.  S. 
Woglum  of  the  U.  S.  Department  of  Agriculture  was 
detailed  to  make  a  comprehensive  investigation  of  the 
whole  subject,  which  he  did  with  marked  success.  Wo- 
glum's  work  in  California  has  been  continued  for  seven 
years  and  has  resulted  in  a  number  of  very  valuable  pub- 
lications and  much  good  to  the  industry. 

The  methods  of  fumigation  have  thus  been  developed 
until  now  it  may  almost  be  considered  a  science  by  itself. 
The  practice  has  spread  to  other  parts  of  the  world,  and 
bids  fair  soon  to  become  the  almost  universal  method  of 
controlling  scale  insects  on  citrus  trees.  Woglum  states 
that  in  the  five  southern  counties  of  California  the  amount 
of  money  spent  on  fumigating  citrus  trees  during  an 
average  '  season  1909-1910  approximated  $1,000,000. 
This  statement  not  only  gives  some  idea  of  the  extent  to 
which  fumigation  is  i)ractice(l,  but  it  shows  what  a  fearful 
tax  and  unnecessary  handicaj)  the  presence  of  scale  in- 
sects place  on  the  citrus  industry. 

The  great  success  of  hydrocyanic  acid  gas  in  controlling 
scale  insects  is  due  to  the  ease  of  its  generation,  and  its 
exceedingly  poisonous  nature.  The  chief  difficulty  has 
been  to  find  the  exact  dosage  which  will  give  maximum 
results  in  the  numbers  of  insects  killed,  and  at  the  same 
time  produce  a  minimum  of  injury  to  the  tree.  The 
different  scales  vary  in  their  susceptibility  to  the  gas,  and 
separate  dosage  tables  have  now  been  worked  out  for  all 
the  important  scales.  For  a  long  time  a  serious  obstacle 
was  the  frequent  burning  of  the  leaves  and  fruit.  This 
was  largely  overcome  by  confining  all  fumigation  to  the 


434  Citrus  Fruits 

night,  when  lower  temperatures  prevailed.  This  was  so 
successful  that  now  all  fumigation  is  done  at  night. 

Tent  fumigation  of  citrus  trees  in  California  at  the 
present  time  is  practically  limited  to  districts  in  the 
southern  part  of  the  state,  although  it  is  being  used  to 
some  extent  in  Tulare  County  in  controlling  the  citricola 
scale.  The  cost  of  fumigating  the  average  sized  tree  is 
about  30  cents,  which  means  an  expense  to  the  growers  of 
$30  to  $40  an  acre.  Fumigation  may  sometimes  be 
necessary  every  season ;  if  thoroughly  done,  however,  it 
may  be  necessary  only  once  in  two  or  three  years. 

Various  systems  are  in  operation  among  the  growers 
for  carrying  on  the  work  of  fumigation.  A  large  part  is 
performed  by  contractors  who  make  a  business  of  fur- 
nishing the  materials  and  doing  the  work  for  a  stipulated 
sum.  Local  associations  in  which  the  growers  cooperate 
for  mutual  protection  and  benefit,  often  own  fumigating 
outfits  and  treat  the  infested  orchards  belonging  to  their 
members.  Such  work  is  usually  done  under  the  super- 
vision of  a  county  inspector  who  sees  that  the  fumigation 
is  properly  done.  In  San  Bernardino  County,  until  quite 
recently,  the  Horticultural  Commission  owned  several 
hundred  tents  and  performed  annually  an  immense  amount 
of  fumigation  w^herever  needed.  This  finally  became 
such  a  great  burden  to  the  Commission  that  the  service 
has  been  discontinued  and  the  work  is  now  done  in 
various  other  ways.  In  many  cases,  private  individuals 
or  companies  having  a  large  acreage  in  citrus  trees 
keep  their  own  fumigating  equipment.  x\t  Highlands, 
California,  an  agreement  has  been  made  by  a  number  of 
growers  in  the  district  for  the  sole  purpose  of  protecting 


Insect  Control  by  Fum.igation  435 

their  orchards  from  scale  and  other  insect  pests,  each 
grower  agreeing  to  share  part  of  the  expense  of  fumigation, 
whether  his  own  orchard  is  infested  or  not ;  the  point 
being  that  the  grower  should  rather  combat  scale  in  some 
orchard  other  than  his  own. 

FUMIGATION    BY    HYDROCYANIC    ACID    GAS 

Fumigation  by  hydrocyanic  acid  gas  is  accomplished 
by  covering  the  trees  at  night  with  air-tight  tents,  and 
placing  under  them  earthenware  gas  generators  contain- 
ing a  mixture  of  sulfuric  acid,  water,  and  either  potas- 
sium or  sodium  cyanide. 

TeiUs 

Fumigation  tents  are  ordinarily  made  of  the  best  eight 
ounce  army  duck  obtainable,  and  vary  in  size,  twenty-foot 
tents  being  large  enough  for  small  trees  and  thirty-six- 
foot  tents  for  the  ordinary  sized  tree.  For  very  large  trees, 
much  larger  tents  may  be  necessary,  although  smaller 
sized  ones  can  be  lapped  over  when  such  trees  are  to  be 
fumigated.  In  order  to  save  material  the  tents  are  made 
in  the  shape  of  an  octagon.  New  tents  are  usually  dipped 
in  a  solution  of  oak  bark  extract  of  tannin,  one  pound  to 
five  gallons  of  water  heated  nearly  to  the  boiling  point. 
The  tents  are  immersed  in  this  hot  solution  for  twenty 
to  thirty  minutes,  after  which  they  are  spread  out  on  the 
ground  to  dry.  This  treatment  is  practiced  to  make  the 
tents  proof  against  mildew,  but  is  not  absolutely  neces- 
sary in  the  climate  of  southern  California,  if  proper  care 
of  the  tents  is  taken  in  the  field  as  well  as  in  storage. 
The  average  length  of  life  of  a  fumigation  tent  is  three  or 


436 


Citni.'t  Fruits 


four  years,  although  the  period  of  usefuhiess  can  of  course 
be  greatly  extended  by  careful  handling. 

In  the  old  system  of  fumigation  the  method  of  calcu- 


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Fig.  150.  —  Method  of  marking  fumigating  tent.     (After  Woglum.) 


lating  the  dosage  for  a  tree  was  mostly  guesswork,  the 
operator  gauging  the  size  of  the  tree  by  eyesight  and 
basing  the  dosage  upon  previous  experience.  Such 
methods  sometimes  produced  fairly  good  results  but  in 


Insect  Control  by  Fumigation  437 

general  the  work  was  very  irregular  and  poor.  The  tents 
now  in  use  are  plainly  marked,  as  shown  in  the  accom- 
panying diagram,  the  measurement:?  being  marked  in  feet 
from  the  center  of  the  tent.  When  the  tent  is  enfolding 
a  tree,  the  distance  over  it  can  readily  be  determined  by 
adding  the  number  that  touches  the  ground  on  one  side 
of  the  tree  to  the  number  that  touches  the  ground  on  the 
opposite  side.  The  two  auxiliary  lines  are  necessary,  as 
in  actual  practice  the  middle  line  may  not  fall  over  the 
middle  of  the  tree  but  to  one  side,  and  in  such  a  case  the 
line  nearest  the  center  is  used  for  measurement.  The  two 
side  lines  may  be  either  three  or  four  feet  from  the  middle 
line. 

Equipment  of   Tents 

For  elevating  the  tents  over  the  trees,  either  poles  or 
derricks  are  used,  the  latter  being  necessary  only  for  very 
tall  trees.  Fourteen-  and  sixteen-foot  poles  are  most 
commonly  used.  One  end  is  sharpened  to  prevent  its 
slipping  on  the  ground.  To  the  other  end  is  fastened  a 
rope  about  three  feet  longer  than  the  pole.  Sometimes 
rings  are  attached  to  the  edge  of  the  tent,  and  these  are 
slipped  over  the  ends  of  the  poles;  it  is  usually  more 
satisfactory,  however,  to  double-lap  the  edge  of  the  tent 
over  the  ends  and  secure  it  firmly  by  a  half-hitch  of  the 
pulling  ropes. 

Generators 

Another  part  of  the  outfit  is  the  set  of  earthen  jars  or 
containers  called  generators.  These  are  made  especially 
for  the  purpose,  usually  without  covers,  and  of  two  gallon 
capacity.     The  two  gallon  size  is  preferred,  as  it  is  large 


438  Citrm  Fruits 

enough  to  accommodate  20  ounces  of  cyanide  in  medium 
sized  lumps  without  boihng  over.  When  trees  requiring 
more  than  this  amount  are  to  be  fumigated,  two  or  more 
generators  may  be  used  under  one  tent.  Generators  with 
Hds  are  desirable  as  the  lids  not  only  aid  in  throwing  the 
gas  outward  but  prevent  spattering  of  the  acid  on  to 
the  tent.  Acid  holes  in  tents  cause  serious  leakage, 
reduce  efficiency,  and  necessitate  frequent  and  expensive 
patching.  So  far,  however,  no  lids  manufactured  have 
proved  entirely  satisfactory.  The  most  imi)roved  type  of 
generator  has  the  outside  of  the  bottom  flat  as  usual  but 
the  inside  of  the  bottom  is  cup-shaped,  with  the  depres- 
sion in  the  center.  This  is  a  great  advantage  when  work- 
ing wdth  very  small  trees  as  it  assures  a  more  thorough 
decomposition  of  the  small  quantity  of  cyanide  used  for 
each  charge. 

Still  another  part  of  the  fumigating  outfit  is  the  supply 
cart  in  which  are  carried  the  cyanide,  sulfuric  acid,  water, 
scales  for  weighing  the  cyanide,  graduated  glass  for  meas- 
uring the  acid  and  water,  rubber  gloves,  dosage  schedules, 
and  lantern.  There  is  on  the  market  an  excellent  supply 
cart  designed  especially  for  this  purpose  which  is  highly 
desirable  where  funds  will  permit,  although  simpler  and 
less  expensive  carts  answer  very  well. 


Cyanide 

Potassium  cyanide  was  used  in  all  fumigation  work  until 
recently.  Now,  however,  sodium  cyanide  is  used  exclu- 
sively for  the  reason  that  it  is  not  only  cheaper  but  will 
supply  a  larger  amount  of  hydrocyanic  acid  gas.     The 


Insect  Control  by  Fumigation  439 

cyanide  should  be  kept  dry  in  storage  and  exposed  to  the 
air  as  little  as  possible,  since  moisture  decomposes  it. 


Acid 

Sulfuric  acid  for  fumigating  should  be  about  66° 
Baume,  which  is  approximately  ninety-three  per  cent 
pure.  It  is  sold  either  in  iron  drums  containing  about 
2000  pounds  or  in  glass  carboys  of  about  ten  gallons 
capacity.  On  account  of  its  corrosive  action  glass  or 
earthenware  containers  are  used  for  distributing  the  acid 
in  the  field.  A  replaceable  copper  or  glass  pipe  fitted  into 
the  bottom  of  the  container  on  the  supply  cart  is  con- 
nected with  a  rubber  tube  bearing  a  large  pinch-cock  for 
regulating  the  flow.  Care  must  be  used  in  handling  the 
acid  as  it  will  quickly  burn  wherever  it  comes  in  contact 
with  the  skin  ;  for  this  reason,  rubber  gloves  are  advisable. 

It  has  been  found  that  the  1-1 1-2  formula  recom- 
mended by  the  Bureau  of  Entomology  is  most  economical 
and  produces  a  complete  reaction.  This  formula  calls 
for  1  fluid  ounce  of  commercial  sulfuric  acid,  1^  ounces 
(avoirdupois)  129  per  cent  sodium  cyanide,  and  2  fluid 
ounces  of  water.  The  water  is  measured  and  placed  in 
the  generator  first,  then  the  acid  is  measured  and  poured 
into  the  water.  Lastly,  when  everything  is  in  readiness, 
the  cyanide  is  weighed  and  placed  in  the  solution,  the 
operator  quickly  retreating  and  closing  the  tent. 

The  addition  of  water  to  the  acid  is  very  important. 
It  dilutes  the  acid  and  raises  the  temperature  of  the 
mixture,  thus  accelerating  the  evolution  of  gas.  The  by- 
product resulting  from  the  reaction  is  sodium  sulfate, 


440  Citrus  Fruits 

a  solid.  The  water  dissolves  this  solid  as  fast  as  it  is 
formed  and  prevents  it  from  forming  a  coating  over  the 
lumps  of  cyanide  and  retarding  the  reaction.  If  sufficient 
water  is  not  used,  the  sulfate  will  solidify,  thus  "freez- 
ing" the  residue,  as  it  is  called.  This  necessitates  extra 
labor  in  emptying  the  generators.  When  concentrated 
acid  is  diluted  with  an  equal  amount  or  more  of  water, 
nearly  pure  hydrocyanic  acid  is  given  off.  If  the  con- 
centrated acid  is  used  without  water  another  gas  known 
as  carbon  monoxide  is  formed. 

The  cyanide  should  always  be  used  in  lumps  about  the 
size  of  a  hen's  egg.  If  finely  powdered  cyanide  is  used,  the 
reaction  is  too  violent  and  endangers  the  operators.  If 
the  cyanide  should  be  dissolved  in  water  before  the  acid 
is  added,  the  reaction  will  be  so  violent  as  to  be  classed 
as  an  explosion,  greatly  endangering  the  operators  and 
injuring  tents  and  trees.  Paper  bags  are  no  longer  used 
for  depositing  the  cyanide  in  the  generators.  Cakes  of 
compressed  cyanide  weighing  one  ounce  each  are  now  on 
the  market,  and  have  proven  very  satisfactory  and 
convenient.  Under  proper  conditions  the  evolution  of 
gas  will  have  been  completed  in  about  five  minutes. 


Operation 

An  orchard  requiring  fumigation  should  be  thoroughly 
examined  regarding  the  slope  of  the  land,  length  of  tree 
rows,  convenience  to  water  supply,  smoothness  of  the 
ground  over  which  the  supply  cart  is  to  be  draw'n,  and 
similar  factors  which  influence  the  ease  of  operation.  A 
tent  and  a  generator  are  unloaded  at  each  tree  and  the 


Insect  Control  hy  Fumigation  441 

tents  unfolded  on  the  side  away  from  tlie  direction  in 
which  they  are  to  be  moved,  ('oniniciiciiiff  at  one  end 
of  the  row,  the  tent  pullers  fasten  the  two  poles  to  the 
edge  of  the  tent  in  the  maimer  previously  described,  place 
the  shari)ened  ends  of  the  poles  on  the  ground  at  the  sides 
of  the  tree  opposite  the  trunk,  and  holding  the  bottom 
of  the  pole  to  the  ground  with  one  foot,  pull  on  the  rope. 
When  the  poles  are  so  elevated  that  they  no  longer  slip, 
each  puller  moves  away  from  the  bottom  of  the  pole  and 
out  from  the  tree  so  that  the  continued  pulling  will  bring 
the  edge  of  the  tent  over  the  tree  and  down  on  the  other 
side.  When  thus  covered,  the  edge  of  the  tent  should 
be  kicked  in  so  that  it  hangs  evenly  all  around  and  does 
not  inclose  unnecessary  space.  After  the  tree  has  been 
fumigated  the  required  length  of  time,  the  tent  can  be 
pulled  over  on  to  the  next  tree  by  this  same  process  with- 
out lowering  it  entirely  to  the  ground. 

The  next  step  in  the  process  is  the  calculation  of  the 
approximate  space  inclosed  by  the  tent  and  the  proper 
dosage  to  use.  Schedules  given  on  pages  450  to  453 
indicate  the  proper  dosages  for  the  principal  citrus  in- 
sects which  require  treatment.  Knowing  the  distance 
over  the  tree  (found  as  previously  directed)  and  the  cir- 
cumference of  the  tent  near  the  base,  one  will  have  no 
difficulty  in  using  the  tables.  The  number  found  at  the  in- 
tersection of  the  vertical  and  horizontal  rows  on  the  table 
indicates  the  number  of  ounces  of  cyanide  to  be  used. 

With  the  ordinary  outfit  of  five  men,  the  work  may  be 
distributed  as  follows  :  two  men  handle  the  tents,  a  third 
takes  the  measurements  and  calls  them  out  to  the  men 
at  the  supply  cart,  who  immediately  consult  the  dosage 


Insect  Control  hi/  Finmgdtion  443 

table,  weigh  out  the  eyanide,  and  measure  the  sulfuric 
aeid  and  water  into  the  generator. 

While  the  cyanide  man  lifts  the  edge  of  the  tent,  the 
other  places  the  generator  underneath.  The  former  then 
puts  in  the  cyanide  and  droj)s  the  tent.  While  the  chemi- 
cal men  are  thus  applying  the  proper  dosage  to  one  tree, 
measurements  are  being  made  on  the  next  and  the  process 
is  repeated  until  the  entire  row  is  fumigated. 

Fumigation  gangs  are  usually  equipped  to  handle  about 
thirty  tents  at  a  "throw,"  as  they  call  it.  When  kept 
busy  these  30  tents  are  "thrown"  or  moved  once  in  every 
forty-five  minutes  or  once  every  hour  as  the  variety  of 
scale  will  determine.  Thus,  except  with  very  large  trees, 
the  number  of  trees  fumigated  per  night  does  not  vary 
according  to  the  size  of  the  trees,  the  difference  simply 
being  a  difference  in  the  time  the  men  have  to  rest  between 
throws,  as  all  must  be  left  over  the  trees  a  stated  period 
of  time.  As  a  rule  fumigators,  when  the  nights  are  favor- 
able, begin  work  about  5  p.xM.,  and  if  the  night  is  not  too 
cool  or  a  fog  arises,  will  work  till  G  a.m.,  giving  a  twelve- 
hour  night  if  an  hour  is  taken  off  at  midnight  for  lunch 
and  rest.  Thus  with  twelve-hour  nights  and  throws  every 
hour,  a  gang  operating  30  tents  will  fumigate  about  3^ 
acres  provided  the  trees  are  planted  regularly  twenty  feet 
apart  each  way.  Fumigating  in  short  rows,  on  contours, 
or  in  rough  ground  is  slower,  of  course. 


Season   of  Finnigatioji 

The  time  of  year  at  w^hich  fumigation  is  done  depends 
upon  two  factors,  the  life-stages  of  the  scale  insect  and 


444 


Citrus  Fruits 


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]'ariou.s  Orchard  Pests  and  their  Control         445 


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446 


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ISI5I5I5I3 

•xaaj  Ni  'HSAO  aoNVisiQ 

Various  Orchard  Pests  and  their  Control 


447 


isisi5:2  2l     l^-f^f?^l     1:^;=;;^^ 

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Mill      M    II    i    1      Mill 

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1    M        \       \             'Ml 

Ml          II     ^                    1        1     1     !     ' 

5I5I5I5ISI      ISiSISgiSiSi      jlgiJIISigiS 

•iaaj  Ni  'aaAO  aoNvxeia 

P3 


il 


O    o 

6? 


448  Citrus  Fruits 

the  condition  of  the  tree  and  fruit.  Most  of  the  fumiga- 
tion in  Cahfornia  is  carried  on  between  the  hitter  ])art  of 
August  and  the  middle  of  January,  as  during  these  months 
the  black  scale  is  most  successfully  reached  and  the  fruit 
is  large  enough  to  escape  the  injury  which  sometimes 
occurs  when  it  is  young  and  tender.  As  previously  men- 
tioned, fumigation  is  ordinarily  done  at  night  when  the 
air  is  cool.  Occasionally  the  work  may  be  done  on  dark 
cool  days,  but  day  work  is  quite  apt  to  result  in  burned 
foliage  and  fruit.  Fumigation  is  not  advisable  when  the 
temperature  falls  below  38°  F.  or  rises  above  65°  F.  as 
the  operator  runs  some  risk  of  injuring  the  trees  if  the 
work  is  done  much  outside  these  limits  of  temperature. 
Another  natural  factor  which  operates  against  successful 
work  is  a  strong  breeze,  w^hich  may  either  hasten  the  escape 
of  the  gas  from  the  tent  or  greatly  injure  the  side  of  the 
tree  on  which  the  gas  becomes  densest.  Cases  of  serious 
injury  to  trees  which  were  said  to  have  resulted  from 
fumigation  when  the  foliage  was  wet  have  been  frequently 
reported.  Careful  experiments  along  tbis  line,  on  the 
other  hand,  show  that  the  presence  of  moisture  on  the  trees 
can  be  ignored  so  far  as  direct  action  of  the  gas  is  con- 
cerned. Due,  however,  to  the  fact  that  the  tents  become 
so  heavy  and  retain  so  much  more  of  the  gas  on  a  wet 
than  on  a  dry  night,  it  is  advisable  to  stop  fumigating 
after  the  foliage  and  tents  become  thoroughly  damp. 

The  insect  pests  against  wdiich  fumigation  is  generally 
directed  are  the  black,  purple,  red,  yellow^,  and  citricola 
scales.  The  susceptibility  of  these  scales  to  the  gas  varies 
more  or  less,  and  accordingly  several  dosage  schedules  have 
been  worked  out.     Experiments  by  Woglum  in  finnigating 


Insect  Control  by  Fumigation  449 

for  the  purple  scale  demonstrated  that  the  best  results 
were  obtained  by  one  and  one-half  ounces  of  potassium 
cyanide  to  every  one  hundred  cubic  feet  of  air  space 
under  the  tent,  the  fumigation  continuing  for  one  hour, 
by  the  end  of  which  practically  all  gas  had  escaped. 
This  is  designated  as  dosage  schedule  A  and  upon  this 
the  other  schedules  are  based.  The  three-quarter  schedule 
for  129  per  cent  sodium  cyanide  is  the  one  almost  univer- 
sally used  at  the  present  time. 

Dosages 

For  the  purple  scale,  dosage  schedule  No.  f  sodium 
cyanide  should  be  used  with  an  exposure  of  one  hour. 

P^or  red  and  yellow  scales,  dosage  schedule  No.  f  is 
recommended  with  an  exposure  of  forty-five  minutes  to 
one  hour. 

For  black  scale,  the  dosage  varies.  When  the  insects 
are  in  the  young  and  tenderer  stages,  f  of  schedule  A  is 
sufficient,  and  it  is  during  these  stages  that  fumigation  is 
advisable. 

Dosage  schedules  A  for  sodium  cyanide  and  No.  110  per 
cent  A  are  reproduced  on  pages  446,  447  and  444,  445 
respectively.  They  have  been  tested  out  experimentally 
in  actual  field  operations  by  Woglum.  Copies  of  these 
schedules  printed  on  cardboard  may  be  secured  from 
the  U.  S.  D.  A.  Bureau  of  Entomology,  or  from  dealers 
in  fumigators'  supplies.  While  using  the  dosage  sched- 
ule in  the  orchard,  it  should  be  framed  with  a  clear 
celluloid  or  glass  cover,  as  otherwise  it  will  soon  become 
so  worn  and  dirty  as  to  be  illegible. 
2g 


450 


CitriLs  Fruits 


New   Woodirorth  Dosage   Table 

C.  W.  Woodworth  has  recently  suggested  a  new  way 
of  calculating  dosage  which  appears  to  have  the  advantage 
of  greater  simplicity  and  accuracy. 


Dosage  Table  —  Sodium  Cyanide 


Relative  Size 

Dose 

Purple  Scale 

Dose 
Black  Scale 

64  ft. 

40    oz. 

20    oz. 

61  ft. 

46    oz. 

18    oz. 

58  ft. 

32    oz. 

16    oz. 

55  ft. 

28    oz. 

14    oz. 

52  ft. 

24    oz. 

12    oz. 

50  ft. 

20    oz. 

10    oz. 

47  ft. 

18    oz. 

9    oz. 

ISIiiiinmm  Dose 

44  ft. 

16    oz. 

8    oz. 

41  ft. 

14    oz. 

7    oz. 

Leakage 

38  ft. 

12    oz. 

6    oz. 

.40% 

36  ft. 

10    oz. 

5    oz. 

33  ft. 

9    oz. 

4|oz. 

30  ft. 

8    oz. 

4    oz. 

.35% 

28  ft. 

7    oz. 

3i  oz. 

26  ft. 

6    oz. 

3    oz. 

24  ft. 

5    oz. 

2ioz. 

.30% 

21ft. 

4    oz. 

2    oz. 

19  ft. 

31  oz. 

If  oz. 

16  ft. 

3    oz. 

Uoz. 

.25% 

2A  oz. 

li  oz. 

2    oz. 

1    oz. 

.20% 

li  oz. 

1  oz. 

1    oz. 

ioz. 

.15% 

|oz. 

\  oz. 

.10% 

(Relative  size  equals  distance  over  plus  1  for  each  5  ft.  of 
difference  between  measurements.) 


Lmed  Control  by  Fuiiur/afion  451 

In  explanation  of  this  new  system  Prof.  Woodworth 
has  submitted  the  following : 

"  The  possibility  of  adding  to  the  distance  over  an 
amount  dependent  on  the  difference  between  the  two 
measurements  which  will  indicate  the  proportionate  size 
of  a  tent  gives  us  what  we  may  call  the  '  relative  size '  of 
the  tent.  If  the  proportions  of  a  tent  remained  constant, 
the  difference  over  could  then  be  taken  as  the  relative  size. 
Since  the  distance  around  always  equals  or  exceeds  the 
distance  over,  we  may  select  as  standard  a  tent  with  these 
two  measurements  equal.  The  amount  to  be  added  to 
this  to  allow  for  wider  and  shorter  tents  is  one-fifth  of  the 
difference  between  the  two  measurements.  Thus  a  tent 
20  X  30  would  have  a  relative  size  of  22,  and  should  have 
a  dose  equal  to  that  of  a  tent  22  X  22. 

"  The  ado])tion  of  this  plan  of  relative  sizes  makes  it 
possible  to  present  a  table  of  dosage  in  a  very  simple 
form,  and  to  make  the  adjustments  for  different  degrees 
of  leakage  also  \'ery  easy. 

"  In  the  foregoing  table  the  first  column  gives  the  rela- 
tive sizes  corresponding  to  the  series  of  doses  shown  in 
the  second  and  third  columns  suitable  for  tents  having 
the  average  leakage  of  25  per  cent. 

"  The  adjustment  for  leakage  is  equally  simple.  Oppo- 
site each  per  cent  given  in  the  table  is  the  minimum  dose. 
Xo  matter  how  small  the  tree,  if  a  tent  leaks  40  per  cent, 
the  dose  for  purple  scale  should  not  be  less  than  12  oz. 
Indeed,  it  is  unwise  to  attempt  to  fumigate  with  a  tent 
of  this  degree  of  leakage  except  when  big  enough  to  hold 
a  sufficient  body  of  gas  without  its  })eing  too  concentrated 
at  the  time  of  generation  for  the  safety  of  the  tree." 


452  Citrufi  Fruits 


Costs 


Cyanide  costs  by  the  ton  about  22  cents  a  pound.  Con- 
tract fumigators  usually  furnish  the  cyanide  at  ;30  cents  a 
pound,  including  the  acid  for  generation.  The  sulfuric 
acid  alone  costs  about  1^  cents  a  pound.  Laborers  receive 
pay  by  the  hour.  The  rate  is  usually  35  cents  an  hour, 
while  the  foreman  receives  50  cents  an  hour.  Most  trees 
fumigated  require  between  five  and  eighteen  ounces  of 
cyanide.  A  supply  cart  completely  equipped  may  be  had 
for  about  $35.  Two  gallon  generators  cost  about  45 
cents  each.  Tents  cost  from  $12  to  $50  each,  according 
to  size.  The  thirty-six  foot  tent  costs  ready-made  from 
$25  to  $30  each.  The  cost  of  thirty  45-foot  tents  of  special 
7-ounce  drill,  together  with  the  other  equipment  necessary 
to  complete  the  outfit,  will  cost  about  $1400. 

Recently  a  fumigating  machine  has  been  invented 
which  quickly  generates  the  gas  in  a  large  metal  drum  by 
mixing  a  water  solution  of  cyanide  and  acid.  The  gas  is 
discharged  directly  into  the  tent  through  a  four-inch  hose. 
The  use  of  this  machine  makes  generators  unnecessary 
and  prevents  all  acid  holes  in  the  tents.  It  is  now  being 
wddely  experimented  with. 


CHAPTER  XXIV 

VARIOUS   ORCHARD  PESTS  AND    THEIR 
CONTROL 

There  are  several  pests  other  than  insects  with  which 
citrus  growers  are  apt  to  have  to  deal.  A  knowledge  of 
the  habits  of  animals  such  as  gophers  and  ground  squirrels 
is  necessary  before  intelligent  methods  of  repression  can 
be  adopted.  Recently  the  citrus  root  nematode  has  at- 
tracted much  attention,  and  a  rather  detailed  account 
of  its  habits  and  life  history  will  no  doubt  prove  of  quite 
general  interest. 

Citrus  Nematode   (Tylenchulus  semi  penetrans) 

As  stated  in  Chapter  XXI  this  worm  has  been  suggested  as 
the  cause  or  one  of  the  causes  of  mottled-leaf.  On  account 
of  the  popular  interest  in  the  nematode  and  the  great  diver- 
sity of  opinions  regarding  it,  space  is  given  to  a  more  or 
less  detailed  account.  The  data  here  presented  has  been 
largely  condensed  and  adapted  from  Cobb.^ 

This  citrus  nematode  was  first  noticed  by  J.  R.  Hodges  of 
Covina,  California,  in  1912,  and  first  mentioned  in  print  by 
B.  R.  Jones.-  A  preliminary  report  was  later  published  by 
E.  E.  Thomas  of  the  University  of  California. 

'  N.  A.  Cobb,  "Citrus-root  Nematode,"  Journal  of  Agri- 
cuUural  Research,  Vol.  II,  No.  3,  June,  1914,  pp.  217-230. 

2  Los  Angeles  County  Hort.  Com.  Bull.  No.  1,  1913,  pp.  72- 
73. 

453 


454  Citrus  Fruits 

This  species  of  nematode  is  found  only  on  the  roots  of 
citrus  trees  although  it  occurs  in  all  parts  of  the  world  where 
citrus  trees  have  been  grown  for  any  length  of  time.  The 
worms  are  very  minute,  being  barely  visible  to  the  unaided 
eye.  The  males  are  smaller  than  the  females  and  probably 
do  not  attack  citrus  roots.  In  fact,  it  is  thought  that  the 
males  do  not  take  food  while  in  the  perfect  stage.  The  eggs 
are  large  and  thin  shelled,  and  are  deposited  one  at  a  time 
in  batches  of  twelve  to  twenty  or  more,  and  are  sometimes 
incased  in  gmiimy  matter.  The  eggs  hatch  in  a  day  or 
two  into  colorless  larvs  which  make  their  way  to  the  nearest 
citrus  root  to  which  the  females  attach  themselves  in  more  or 
less  well  defined  groups.  These  groups  are  very  quickly 
scattered  along  the  fine  fibrous  feeding  roots  in  enormous 
numbers.  The  effect  is  to  sap  the  vitality  of  the  tree  and 
kill  the  feeding  roots.  The  movements  are  slow  and  weak 
and  the  worms  cannot  migrate  through  the  soil  to  any  great 
distance. 

The  females  possess  an  oral  spear  with  which  they  force 
the  head  end  into  the  tissues  of  the  root.  That  part  of  the 
body  within  the  root  enlarges  somewhat  so  that  it  is  impos- 
sible for  them  to  withdraw.  They  remain  fixed  for  the  rest 
of  their  lives,  although  the  exposed  part  of  the  body  may  be 
moved  back  and  forth.  The  food  consists  of  sap  and  pro- 
toplasmic cell  contents.  The  entire  life  cycle  occupies  from 
six  to  eight  Aveeks. 

A  predaceous  nematode  of  large  size  (]\IononcJms  payil- 
latus)  has  been  foimd  to  occur  also  in  the  soil  about  citrus 
roots.  The  Mononchus  preys  regularly  upon  the  males  and 
larvae  of  Tylenchulus,  swallowing  them  whole.  To  what 
extent  the  Mononchus  may  be  able  to  control  the  citrus 
nematode  is  not  at  present  known. 

The  citrus  nematode  affects  the  different  stocks  about 


Variouft  Orchard  Pests  and  their  Control         455 

equally.     It  has  so  far  been  found  in  abundance  on  the  sour, 
sweet,  and  trifoliate  oranges  and  on  pomelos. 

"  There  can  be  no  doubt  that  Tylenchulus  scini penetrans  is 
an  injurious  parasite.  There  is  conclusive  evidence  that  it 
kills  the  feeding  roots  of  citrus  trees.  The  roots  die  either  as 
a  direct  result  of  the  attack  of  this  parasite  or  of  the  attack 
of  other  organisms  following  in  its  wake ;  in  other  words, 
the  nematode  is  a  primary  cause  of  the  death  of  the  feeding 
roots.  Many  cases  have  come  under  observation  in  which 
it  was  apparent  that,  had  it  not  been  for  the  nematode,  the 
roots  would  have  remained  in  a  healthy  condition.  The 
evidence  along  these  lines  is  of  the  same  character  as  that 
which  is  relied  on  in  demonstrating  injuries  due  to  insects 
and  other  macroscopic  parasites. 

"The  extent  of  the  damage  which  may  properly  be  charged 
up  against  this  parasite  is  a  different  matter,  and  it  will  be 
necessary  to  collect  evidence  along  this  line  for  several  years 
before  a  final  statement  can  be  made.  Up  to  the  present 
the  data  obtained  indicate  unquestionably  that  the  investi- 
gations should  be  continued." 

The  citrus  nematode  is  very  readily  distriliuted  from  place 
to  place  on  the  roots  of  imrsery  stock,  and  this  is  especially 
true  when  the  trees  are  balled  for  shipment.  The  question 
as  to  just  how  much  importance  to  place  upon  inspection  and 
quarantine  in  connection  with  this  parasite  cannot  be  an- 
swered at  the  present  time.  In  order  to  be  on  the  safe  side 
it  is  well  for  buyers  to  specify  that  the  trees  be  free  from 
nematodes.  Control  measures  such  as  injecting  carbon 
bisulfide  and  lime  water  into  the  soil  are  l)eing  widely  ex- 
perimented with,  but  so  far  without  any  very  promising  re- 
sults. Vaile^  has  shown  that  nematodes  are  killed  by  sub- 
mersion in  hot  water  at  a  temperature  of   120°  F.  for  ten 


1  Annual  Rpt.  Ventura  County  Hort.  Com. 


1913,  p.  10. 


456  Citrus  Fniits 

minutes.  This  treatment  did  not  kill  the  roots  entirely,  al- 
though some  of  the  fine  feeding  roots  were  injured.  This 
is  not  considered  important  because  when  trees  are  trans- 
planted with  bare  roots  they  put  out  new  feeding  roots 
anyway.  It  is  possible  that  some  such  method  of  treatment 
may  soon  be  devised  by  which  infested  nursery  stock  may  be 
freed  from  the  pest. 

The  Pocket   Gopher   (Gcomys   hursnriu.s) 

Gophers  often  cause  serious  damage  to  citrus  trees  by 
girdling  young  trees  at  the  surface  of  the  ground  and  by  chew- 
ing the  bark  from  the  crown  roots  of  older  trees.  They  are 
especially  troublesome  in  orchards  near  alfalfa  fields  in  sec- 
tions where  open  ditches  are  used  for  irrigation.  Gophers 
will  run  for  considerable  distances  over  the  surface  of  the 
ground  at  night,  and  entering  an  orchard  without  warning 
begin  to  dig  their  runways.  The  runs  extend  for  long  dis- 
tances underground  and  are  vexatious  nuisances  when  irri- 
gating. Gophers  may  be  controlled  both  by  poisoning  and 
by  trapping. 

In  trapping  use  a  small  wire  spring  trap  and  set  it  delicately 
so  it  will  spring  easily.  Then  open  the  run  under  a  recently 
made  pile  of  fresh  dirt  and  insert  the  trap,  pushing  it  well 
back  into  the  run.  If  the  run  goes  both  ways,  put  in  two 
traps  to  make  sure.  Then  close  up  the  holes  with  grass  or 
sod  so  that  just  a  little  light  can  enter.  The  gopher  will 
soon  notice  the  light,  and  in  attempting  to  close  the  opening 
will  be  caught.  It  is  well  to  attach  a  long  string  to  the  trap  to 
prevent  their  being  lost  if  pulled  for  some  distance  back  into 
the  hole.  Any  attempt  to  drown  a  gopher  Viy  turning  irrigation 
water  into  the  hole  will  not  succeed  unless  the  entire  surface 
of  the  ground  can  be  flooded  as  is  possible  in  alfalfa  fields. 

Strychnine  is  probably  the  most  effective  and  safest  poison 


Varions  Orchard  Pests  and  their  Control         457 

for  general  use.  A  sirup  poisoned  with  strychnine  is  very 
easily  prepared  and  will  he  found  very  effective.  It  is  made 
according  to  the  following  formula  recommended  by  the 
U.  S.  Bureau  of  Biological  Survey:  "Dissolve  an  ounce  of 
strychnia  sulfate  in  a  pint  of  boiling  water.  Add  a  pint  of 
thick  sugar  sirup  and  stir  thoroughly.  The  sirup  is  usually 
scented  by  adding  a  few  drops  of  oil  of  anise,  but  this  is  not 
es.sential.  If  preserved  in  a  closed  vessel,  the  sirup  will  keep 
indefinitely."  This  quantity  will  poison  about  thirty  pounds 
of  shelled  corn  or  grain,  preferably  corn.  The  grain  should 
be  soaked  in  water  overnight  and  then  soaked  for  several 
hours  in  the  poisoned  sirup.  The  dry  strychnine  may  also 
be  used  by  introducing  a  very  small  quantity  on  the  point 
of  a  knife  into  carrots,  beets,  sweet  potatoes,  entire  raisins, 
or  prunes.  Such  poisoned  bait  is  then  placed  carefully  in 
the  freshly  open  holes,  or  in  the  runways.  There  are  many 
prepared  gopher  poisons  on  the  market  which  may  be  pur- 
chased if  one  does  not  care  to  go  to  the  trouble  of  mixing  the 
strychnine  as  directed. 

The  use  of  carbon  })isulfide  for  killing  gophers  is  recom- 
mended where  the  soil  is  moist  and  the  burrows  not  too  ex- 
tensive. In  dry  soil,  the  gas  escapes  too  rapidly  to  make  its 
use  effective.  The  bisulfide  may  be  poured  over  a  btuich  of 
cotton  waste  or  other  material  and  this  pushed  cjuickly  into 
the  burrow,  which  should  be  closed  at  once.  Since  carbon 
bisulfide  is  highly  inflammable  a  very  common  method  of  ap- 
plication is  to  ignite  the  cotton  waste  after  it  is  placed  in 
the  burrows  as  deeply  as  possible ;  the  gases  produced  by 
ignition  are  poisonous  and  seem  just  as  effective  a  killing 
agent  as  the  liquid  bisulfide.  On  account  of  the  danger  of 
explosion  to  the  operator  and  the  liability  of  starting  grass 
fires,  the  use  of  bisulfide  by  ignition  is  not  so  advisable  as  by 
the  former  method.     Special  injectors  for  forcing  the  l)isulfide 


458  Citrus  Fruits 

into  the  Inirrows  are  on  the  niiirket  and  are  more  effeetive 
than  the  hand  method. 

Reeently  a  new  method  of  attack  has  been  (Hscovered  which 
is  said  to  work  well  where  only  a  few  gophers  have  to  be 
dealt  with.  An  automobile  is  placed  over  the  hole  and  a  short 
hose  attacked  to  the  exhaust,  the  other  end  being  inserted 
in  the  gopher  hole  and  packed  with  moist  soil.  After  turning 
an  extra  amount  of  luV)ricating  oil  into  the  cylinders  for  the 
purpose  of  making  a  smoky  gas,  the  engine  is  started.  If 
smoke  is  emitted  from  any  hole  in  the  vicinity  it  is  promptly 
plugged.  A  few  minutes  of  this  treatment  naturally  pro- 
duces a  condition  fatal  to  the  gopher. 

Ground   Squirrrlfi   (CiteUus  hrrchryi) 

These  animals  overrun  California,  occurring  by  millions 
in  the  interior  valleys,  where  they  destroy  large  quantities 
of  grain,  almonds,  and  dried  fruit.  They  may  do  great  dam- 
age to  citrus  orchards  and  nurseries  but,  unlike  the  gopher, 
their  depredations  are  largely  confined  to  orchards  situated 
near  grain  fields  or  brush  land.  Railroad  embankments, 
canal  banks,  and  roadsides  are  favorite  places  for  squirrel 
burrows.  The  animals  live  mostly  on  grain,  nuts,  acorns,  and 
weed  seeds,  but  during  the  rainless  summer  and  fall,  when 
the  green  herbage  dries  up,  they  are  apt  to  visit  citrus  trees 
and  gnaw  the  bark.  A  few  squirrels  may  quickly  ruin  a 
large  number  of  trees  when  the  young  trees  have  just  been 
planted  out. 

Ground  squirrels  may  be  poisoned  in  the  same  way  as 
gophers,  poisoned  barley  or  wheat  being  most  commonly  used 
for  this  purpose.  Whole  barley  threshed  but  still  retaining 
its  rough  outer  husk  will  not  be  eaten  by  birds,  so  it  should 
always  be  used  in  this  form.  The  following  formula  and  di- 
rections for  preparing  poisoned  barley  are  suggested  : 


Various  Orchard  Pests  and  their  Control         459 

Whole  barloy 20     pounds 

Vinegar I5  pints 

Strychnia  sulfate        1     ounce 

Honey 1     pint 

Cyanide  of  potassium I5  ounces 

Eggs 1     dozen 

Pulverize  the  strychnine  in  the  vinegar  and  see  that  it  all 
dissolves.  Dissolve  the  cyanide  in  a  little  water.  Beat  the 
eggs  thoroughly.  Mix  all  the  ingredients  together  and  stir 
well  before  adding  to  the  barley.  Stir  at  intervals  during 
the  next  few  hours  and  dry  before  using  as  it  will  mold  if  put 
away  wet.  Grain  coated  with  poison  is  more  effective  than 
grain  soaked  in  poison  for  the  reason  that  much  of  the  grain 
being  gathered,  carried  into  the  burrows  and  stored  for 
winter  use  is  not  immediately  effective.  When  the  grains 
are  coated  with  poison,  enough  will  be  absorbed  by  the  cheek 
pouches  during  transit  to  produce  death. 

Another  very  effective  poison  during  the  dry  season  is 
halved  ripe  cull  oranges,  upon  the  cut  surfaces  of  which 
strychnine  has  been  smeared. 


CHAPTER    XXV 
BIBLIOGRAPHY 

OTHER  BIBLIOGRAPHIES 

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REFERENCES   TO   LITERATURE   DEALING   WITH   PAR- 
TICULAR  FRUITS 

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Blhli()(jr(i})li!/  483 

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Fertilization 

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INDEX 


PPOPERTT  imAST 
N.  C.  State  College 


Abrasions,  how  caused,  278. 

Absentee  ownership,  356. 

Acid,  .contained  in  fruit,  63  ;  sul- 
furic for  fumigation,  439  ;  loss  of 
in  respiration,  287. 

Acreage,  citrus,  in  California  by 
counties,  22 ;  in  California  in- 
creasing, 354. 

Advertising,  division  of  Exchange, 
350,  351. 

Agents,  bonded  salesmen  of  Ex- 
change, 348. 

Air,  importance  of  in  soil,  165. 

Alfalfa,  as  interculture  crop,  159 ; 
as  a  mulch,  173 ;  as  cover-crop, 
182. 

Alignment,  of  fruit  in  box,  138. 

Alternaria,  affecting  stored  lemons, 
382. 

Alternaria  citri,  causing  fruit  decay, 
388. 

Ammonia  compounds,  prejudicial 
to  citrus  trees,  372 ;  as  a  cause 
of  mottled-leaf,  379. 

Analyses  of  soils,  175. 

Antiquity  of  citrus  fruits,  use  in 
Hebrew  ceremonies,  40. 

Aphids,  427. 

Aphis  gossypii,  427. 

Aramigus  fuUeri,  429. 

Arizona,  citrus  production  in,  23. 

Armillaria  mellea,  145,  373. 

Artesian  wells,  for  irrigating,  192. 

Artificial  coloring,  by  sweating, 
284 ;  federal  legislation  regard- 
ing. 285. 


Asher,  J.  M.,  20. 

Asphaltum,  paint  for  wounds,  227 ; 
in  fuel  oil,  260 ;  for  wash  tanks, 
386. 

Aspidiotus  hederae,  420. 

Aspidiotus  rapax,  420. 

Assessments,  for  expenses  of  Ex- 
change, 348. 

Associations,  345 ;  affiliated  with 
Exchange,  301  ;  first  organized, 
8;   organization  of,  351. 

Atmometer,  records  at  Whittier 
and  Riverside,  189. 

Atmospheric  humidity,  effect  on 
citrus  trees  and  fruit,  34. 

Aurantium,  derivation  of  word,  41. 

Australia,  frost  in,  25 ;  introduc- 
tion of  Navel  orange,  15 ;  ship- 
ping oranges  to,  344  ;  source  of 
cottony  cushion  scale,  6. 

Australian  Navel  orange,  introduc- 
tion of,  16. 

Australian  type,  128. 

Automatic  weighing,  of  individual 
grades,  292. 

Automobile,  used  in  killing  gophers, 
458. 

Azores,  15,  70. 

Backus,  W.  H.,  58. 

Bacteria,  in  soil,  165. 

Bacterium  citriputcale,  401. 

Bags,  for  picking,  280. 

Bahia,  Brazil,  birthplace  of  Navel 

orange,  13. 
Balling,  nursery  stock,  104. 


505 


506 


Index 


Bare  rooted,  trees  for  planting,  157. 

Bark,  effect  of  Botrytis  vulgaris  on, 
366  ;  gnawed  by  squirrels,  458  ; 
new  growth  of,  chlorophyll  in, 
49 ;  of  sour  orange  resistant  to 
gum-disease,  366. 

Barnyard  manure,  cost  of,  361. 

Barometer,  indicating  frost,  237. 

Baronio  system  of  pruning,  214. 

Bench-roots,  89. 

Bergamot  oil,  imported,  332  ;  tariff 
on,  9. 

Beveling  machines,  293. 

Bibliography,  general,  461. 

Bigelow,  W.  D.,  288. 

Bioletti,  F.  T.,  quoted,  240. 

Bisulfide  of  carbon,  for  killing 
gophers,  457. 

Biting  insects,  405. 

Bitter  orange,  origin  of,  introduc- 
tion into  Florida,  41. 

Black  leaf  extract,  as  a  spray  for 
thrips,  427. 

Black  pit  of  lemon,  401. 

Black  rot  of  Navel,  388. 

Black  scale,  general  discussion  of, 
405. 

Black  smut,  290. 

Blasting,  to  facilitate  irrigation, 
203,  hard  soil,  156;  to  ame- 
liorate soil,  146. 

Blemishes,  importance  in  judging, 
134;    of  fruit,  318. 

Blizzards,  237. 

Blue  mold,  387. 

Bluestone,  as  a  disinfectant,  385. 

Bolting  split  limbs,  229. 

Bolton,  J.  P.,  252. 

Bonavia,  E.,  60. 

Boosting  plants,  193. 

Bordeaux  mixture,  for  seed-bed 
gumming,  89,  369 ;  for  wither- 
tip,  381 ;   for  damp-off,  392. 

Bordeaux  paste,  for  gum-disease, 
366  ;    for  pruning  wounds,  228. 

Botany  of  citrus,  bibliography,  485. 


Botrytis  vulgaris,  causing  gum- 
disease,  366  ;  causing  fruit  decay, 
388. 

Box,  dimensions  of  lemon  box,  310  ; 
material,  kind  of,  293 ;  cost  of, 
293  ;    shooks,  292. 

Boxes,  machines  for  making,  293 ; 
materials  for,  292  ;    size,  293. 

Breeding,  references  to  literature, 
479  ;    for  frost  resistance,  244. 

Brehm,  14. 

Brokerage  charges,  compared  with 
Exchange  costs,  351. 

Brown  rot  fruit  decay,  386. 

Brown  rot  fungus,  transmission  by 
rain,  281 ;  regions  most  seriously 
affected,  282. 

Brown  rot  gum-disease,  364. 

Brown  spot,  of  Navel  orange,  326 ; 
description  of,  389. 

Bruises,  321. 

Brushing,  removal  of  dust  by  dry 
brushing,    with  water,  291. 

Buckwheat,  as  cover-crop,  182. 

Budding,  time  of,  95  ;  nursery  stock, 
92;  method  of,  95;  high  bud- 
ding on  sour-stock,  97  ;  dormant 
buds,  98  ;  cost,  99. 

Bud-sports,  120;  how  pruned,  211. 

Bud  variation,  118. 

Bud-wood,  selection  of,  93,  128. 

Burr  clover,  as  cover-crop,  182. 

By-product  industry,  needed  in 
California,  354. 

By-products,  references  to  litera- 
ture, 492  ;    importation  of,  331. 

California  Fruit  Growers'  Exchange, 
history  and  organization  of,  345. 

California  Navel  Orange,  chemical 
analysis  of,  62. 

California  pruning  saw,  225. 

Canada  field  peas,  as  cover-crop,  182. 

Canker,  description  of,  392. 

Capital,  estimating  amount  needed, 
360  ;    of  Exchange,  348. 


Index 


507 


Capital  required,  358. 

Capitalization,  356. 

Carbon  bisulfide,  for  killing  gophers, 

457. 
Carbon  dioxide,  loss  of  from  fruit, 

61. 
Car-load,    number    of    boxes    con- 
tained, 310. 
Cars,   standard,    295;     other   than 
standard,  275  ;  air  spaces  in,  296 ; 
bracing  of  boxes  in,  296 ;    freisht 
on,  297;    icing  charges,  297. 
"Car  Squeeze,"  296. 
Cement  dust,  on  fruit,  324. 
Central  exchange,  348. 
Ceratitis  capitata,  109. 
Chambers  of  Commerce,  influence 

of,  11. 
Chapman,  A.  B.,  16. 
Chapman,  C.  C,  71. 
Characters,  segregation  of,  120. 
Chemical    Analyses    of    California 

Oranges  and  Lemons,  62. 
Chemical  fertilizer,  cost  of,  361. 
Chemistry,  references  to  literature, 

486. 
Chemistry  of  citrus  fruits,  61. 
Chenopodium,  as  a  cover-crop,  183. 
Chimeras,  120. 

Chinese  lemon,  as  a  root-stock,  154. 
Choice,  grade,  292. 
Chrysomphahis  aurantii,  411;  var. 

citrinus,  414. 
Citellus  beecheyi,  458. 
Citranges,  79. 
Citrate    of    lime,    imported,    332; 

tariff  on,  9. 
Citric  acid,  imported,  332 ;    manu- 
facture of,  333  ;    tariff  on,  9. 
Citricola  scale,  discussion  of,  419. 
Citron,  preparation  of,  337  ;  bibliog- 
raphy, 473  ;   grown  in  California, 
susceptibility  to  frost,  variety  Cor- 
sica, 80  ;  imported,  332  ;  introduc- 
tion into  Italy,  41 ;  susceptibility 
to  frost,  242  ;  tariff  on,  9. 


Citrus  areas  of  California,  southern 
coast,  interior  valleys,  northern 
coast,  26. 
Citrus  aurantifolia,  43,  45. 
Citrus  aurantium,  43. 
Citrus  bergamia,  43. 
Citrus  bibliography,  473. 
Citrus  canker,  description  of,  392. 
Citrus  decumana,  43,  44. 
Citrus  japonica,  43,  44. 
Citrus  Imionia,  43,  45. 
Citrus  mealy  bug,  421. 
Citrus  medica,  43,  45. 
Citrus  nobilis,  43. 
Citrus  Protective  League,  353. 
Citrus  sinensis,  43. 
Citrus  species  in  North  and  South 

America,  42. 
Citrus  trifoliata,  43. 
Cladosporium  citri,  395  ;  herbarum 

var.  citricolum,  395. 
Classification,  42. 
Clausen,  R.  E.,  cited,  381. 
Clearing  land,  cost  of,  359. 

Cleats,  proper  position  of,  138. 

Climate,  interior  valleys,  30  ;  north- 
ern coast,  31 ;  southern  coast 
division,  28. 

Clipper  cuts,  321. 

Clippers,  abrasions  caused  by,  278. 

Clouds,  as  affecting  frost,  235. 

Cobb,  N.  A.,  cited,  449. 

Coccus  hesperidum,  418. 

Colby,  G.  E.,  288. 

Cold  periods,  historical,  230. 

College  of  Agriculture,  service  of, 
358. 

Colletotrichum  gloeosporioides,  380. 

Collins,  J.  F.,  cited,  228. 

Color,  importance  in  judging,  136. 

Coloring  process,  results  of  too 
rapid  forcing,  290. 

Combustion,  in  orchard  heaters, 
253. 

Conmiission  men,  344. 

Concrete  irrigating  pipe,  194. 


508 


Index 


Conduction,  233. 

Consumption,  increase  of,  354. 

Contour,  planting,  150. 

Convection,  233. 

Cooperation,  first  tried,  8 ;  in  frost 
fighting,  274. 

Cooperative  packing-houses,  345. 

Copley,  Edward,  252. 

Coquillett,  D.  W.,  431. 

Core  rot,  of  stored  lemons,  382. 

Correspondence  course,  in  citrus 
fruits,  358,  11. 

Cost  of  production,  355. 

Costs,  of  bringing  orchard  into  bear- 
ing, 359. 

Cotton  Exposition,  held  in  New 
Orleans,  6. 

Cottony  cushion  scale,  discussion 
of,  417  ;  fumigation  for,  431  ;  in- 
troduced, 6. 

Cottony  mold,  383. 

Cottony-mold  fungus,  on  vetch 
cover-crop,  182. 

County  Commissioners  of  Horti- 
culture, 110. 

Cover-crop,  advantages  of,  181  ; 
disadvantages  of,  182 ;  kinds, 
182  ;  references  to  literature,  484  ; 
harbors  cottony  mold,  383 ; 
plowed  under,  166 ;  relation  to 
mottled-leaf,  379. 

Cover,  T.  D.,  first  exhibited  Navel 
orange,  18. 

Cowpeas,  as  cover-crop,  182. 

Cracks,  in  oranges,  326. 

Craw,  Alexander,  20. 

Creosote,  227. 

Cross-furrowing,  for  irrigation,  201. 

Cross-pollination,  123,  115,  116. 

Crown  gall,  occurs  on  citrus, 
401. 

Cucumber  beetle,  430. 

Culls,  removal  of,  315. 

Cultivation,  165 ;  depth  of,  fre- 
quency of,  168. 

Cultivator  scars,  on  fruit,  321. 


Curing,  advantages  of,  278 ;    refer- 
ences to  literature,  489. 
Cuttings,  propagation  by,  92. 
Cyanide,  438. 

Damp-off  fungus,  in  seed-bed,  88. 
Damping  off,  of  seed-bed  stock,  391. 
De  Candolle,  40. 
Decay,    in    pruning   wounds,    226 ; 

in  transit,  effect  of  icing  on,  297  ; 

in  oranges,     causes  of,    277 ;    in 

dropped    fruit,    279 ;     in    stored 

lemons,  308 ;    splits  a  cause  of, 

327. 
Defoliation,  by  frost,  242. 
Degenerate  types  of  trees,  357. 
Degeneration     of     trees,     due     to 

suckers,  209. 
Demonstration  trains,  influence  of, 

11. 
Desiccating   winds,    cause   of   twig 

gumming,  367. 
Dew,  as  affecting  frosts,  235. 
Dew  point,  raising  of,  246. 
Diabrotica  soror,  430. 
Die-back,  see  exanthema,  369. 
Digging  holes,  for  trees,  155. 
Dimorphic     branches,     of     orange 

trees,  208. 
Diplodia     rot,     due     to     Diplodia 

natalensis,  397. 
Discount,  in  cars  other  than  stand- 
ard, 295. 
Diseases,      prevention      important, 

357  ;   bibliography,  499  ;   control, 

364. 
Disinfection,  of  wash  water,  385. 
Distance  apart,  of  trees,  149. 
Distillate  oil,  as  a  spray  for  scale, 

432. 
Distributing  costs,  352. 
Distribution,  of  fruit  by  Exchange, 

348. 
District  exchange,  347. 
Diversion  of  cars,  right  of,  298. 
Domestic  recipes,  341. 


Index 


509 


Dosage  for  fumigation,  calculating, 

441,444;    schedules,  444-447. 
Double  clipping,  279. 
Dressings  for  wounds,  227. 
Dropped  fruit,  decay  of,  279. 
Dry  center,  of  lemons,  329. 
Drying,  of  fruit,  291. 
Dynamite,  146. 

Early  ripening,  of  oranges  in 
Northern  California,  288. 

Early  shipments,  losses  in,  283. 

Electric  orchard  heaters,  250. 

Electric   railways,    influence  of,  10. 

Elevation,  effect  of  in  Interior 
VaUey,  30. 

Elm,  affected  by  mottled-leaf,  376. 

Employees,  provision  for,  316. 

Englehardt,  J.  P.,  69. 

Enzymatic  fermentation,  of  fruit, 
61. 

Eriophyes  oleivorus,  424. 

Erodium,  as  cover-crop,  183. 

Essence  of  orange  flowers,  338. 

Essential  oils,  manufacture  of,  334. 

Etrog,  40. 

Eucalyptus,  affected  by  mottled- 
leaf,  376. 

Eureka  lemon,  pollination  of,  55 ; 
chemical  analysis  of,  62 ;  how 
pruned,  214. 

Euthrips  citri,  425. 

Evaporation,  as  affecting  tempera- 
ture, 233 ;  from  porous  cup 
atmometers,  189  ;    from  soil,  165. 

Ever-sporting  trees,  211. 

Exanthema,  causing  blemishes  on 
fruit,  325  ;    description  of,  369. 

Exchange,  relation  to  other  selling 
agencies,  345  ;  cost  of  operating, 
351 ;  Southern  California  Fruit 
Exchange  first  organized,  8. 

Exhibitions,  judging  fruit  at,  132  ; 
influence  of,  12. 

Explosions,  in  orchard  heaters, 
255. 


Fairs,  first  citrus  fairs,  5. 

Fancy,  grade,  292. 

Fawcett,  H.  S.,  cited,  397. 

Feature  exhibits,  judging,  138. 

Federal  Board  of  Food  and  Drugs 
Inspection,  ruling  regarding  col- 
oring of  green  citrus  fruits,  285  ; 
effect  of  ruling  regarding  artificial 
coloring,  285. 

Fenugreek,  as  cover-crop,  182. 

Ferrarius,  John  Baptiste,  13. 

Fertilization,  of  seed-bed,  88;  bib- 
liography, 483  ;  of  nursery  stock, 
92;  of  orchards,  175;  a  type  of, 
178. 

Fertilizer,  in  planting  holes,  157 ; 
cost  of,  359. 

Field  box,  ratio  of  to  packed  box, 
295. 

Filaree,  as  cover-crop,  182. 

Fingered  lemons,  120. 

Flavor,  importance  in  judging,  136. 

Florida  Citrus  Exchange,  organiza- 
tion of,  353. 

Flowers  of  citrus,  description, 
season,  52 ;  of  lemon,  different 
kinds  of,  54. 

Fluctuations,  118,  128. 

Foot-rot,  372. 

Form,  importance  in  judging,  133. 

Fortunella,  43. 

Freezing  in  transit,  prevention  of, 
298. 

Freight,  cost  of,  360. 

Freight  rate,  on  lemons,  312. 

Freight  rates,  297. 

Friendly  fungi,  396. 

Frost,  effect  on  fruit  on  lower 
branches,  281  ;  in  countries  pro- 
ducing citrus  fruits,  25;  hazard, 
33  ;  air  currents,  34  ;  effect  on 
value  of  land,  140;  where  to  be 
expected,  140;  of  January,  1913, 
231  ;  losses  from,  232;  factors 
influencing,  234  ;  local  conditions 
affecting,    236 ;     relative    resist- 


510 


Index 


ance  to,  242  ;  causing  bleiiiishes 
on  fruit,  325  ;  a  frequent  cause 
of  failure,  357. 

Frost  fighting,  bibliography,  494. 

Frost  hazard,  judgment  of,  141. 

Frost-injured  fruit,  references  to 
literature,  494. 

Frost  injury,  to  vegetable  tissues, 
239  ;  on  leaves,  368 ;  prevention 
of,  243. 

Frost  protection,  average  cost  of, 
361. 

Frosted  fruit,  separation  of,  270. 

Frosted  trees,  how  pruned,  217. 

Frosts,  as  affected  by  winds,  233  ; 
in  Florida,  230 ;  in  California, 
231  ;  season  of  in  California,  232  ; 
forecasting,  233. 

Froude,  Charles,  252. 

Frozen  fruit,  changes  in,  241  ; 
edible,  241  ;    loss  of  juice,  241. 

Fruit  Growers'  Supply  Co.,  organi- 
zation, 301  ;  purpose,  301  ;  ac- 
complishments, 301. 

Fuel  oils,  properties  of,  260 ;  stor- 
age of,  262. 

Fuller's  rose  beetle,  429. 

Fumigating,  machine,  452  ;  cost  of 
materials,  452 ;  cost  of,  361  ; 
done  by  associations,  347  ;  large 
seedlings  difficult  to  cover  with 
tents,  65. 

Fumigation,  431  ;  season  of,  443  ; 
operation,  440 ;  cost  of,  448 ; 
efficiency  of,  403  ;  bibliography, 
497  ;    scars,  322. 

Fumigator's  supply  carts,  438. 

Furrows,  for  irrigation,  201. 

Fusarium,  causing  damp-off,  391. 

Galloway,  B.  T.,  quoted,  239. 
Galls,  on  citrus  trees,  401. 
Garey,  T.  A.,  4,  71,  74;    introduc- 
tion of  varieties,  16. 
Generators,  fumigation,  437. 
Geomys  bursarius,  456. 


Germ-plasm,  211. 

Glaced  kumquats,  341. 

Gloeosporium  limetticolum,  381. 

Gopher,  456. 

Gore,  H.  C,  288. 

Grades,  of  fruit,  292. 

Grading,  fruit,  292  ;  land,  cost  of, 
359. 

Grafting,  nursery  stock,  92. 

Grape  fruit,  see  pomelo,  75. 

Gravity  frost,  237. 

Gray  mold,  of  fruit,  388. 

Gray  scale,  419. 

Greedy  scale,  420. 

Green  manure  crops,  181. 

Green  manuring,  references  to  litera- 
ture, 484. 

Green  mold,  387. 

Ground  squirrels,  458. 

Growth  rings,  in  wood  of  lemon, 
47. 

Guaymas,  citrus  industry  at,  24. 

Gum-disease,  of  seed-bed  stock,  89, 
368  ;  in  pruning  wounds,  229  ; 
caused  by  tillage  implements, 
172  ;  carried  by  shoes  of  pickers, 
280. 

Gum-diseases,  364. 

Gum,  formation  along  cambium,  49. 

Gumming,  resistance  of  sour  stock 
to,  152. 

Hail  scars,  323. 

Hairy  vetch,  as  cover-crop,  182. 

Hammon,  W.  H.,  cited,  235. 

Hardpan,  143  ;  presence  of,  in  In- 
terior Valley,  31  ;  as  affecting 
irrigation,  203. 

Harrowing,  168. 

Hart,  E.  H.,  71. 

Harvest  season,  of  oranges,  of 
lemons,  63. 

Hauling  fruit,  average  cost  of,  360. 

Heading  back,  nursery  trees,  100. 

Heading  trees,  205. 

Heat,  loss  of,  233. 


Index 


511 


Hedges,  Florence,  cited,  401. 

Hemispherical  scale,  420. 

Hermosillo,  citrus  planting  at,  24. 

Hesperides,  The,  13. 

Hesperidin,  241. 

Hexagonal  planting,  14<S. 

HUgard,  E.  W.,  quoted,  196,  431. 

Hodges,  J.  R.,  cited,  378,  449. 

Hoeing,  under  trees,  172. 

Holes,  for  tree  planting,  155. 

Holt,  L.  M.,  18. 

Honey-dew,  407 ;  excreted  by 
mealy  bug,  421. 

Hongkong,  shipping  oranges  to,  344. 

Horticultural  inspection,  cost  of, 
111. 

Hume,  H.  H.,  76. 

Humidity,  for  stored  lemons,  308. 

Humus,  produced  by  mulch,  173  ; 
general  discussion  of,  178 ;  lack 
of,  a  cause  of  mottled-leaf,  378. 

Hybridization,  115. 

Hybridizing,  facility  of  between 
species,  42. 

Hybrids,  production  of,  distribu- 
tion of,  79. 

Hydrocyanic  acid  gas,  first  used  in 
fumigation,  431. 

Icerya  purchasi,  description  of, 
417 ;  introduced,  6. 

Icing  charges,  297. 

Icing  of  cars,  effect  of  precooling 
on,  298. 

Icing,  of  lemons  in  transit,  312. 

Ikeda,  T.,  56. 

Immature  fruit,  sweating  of,  282  ; 
shipment  of,  283  ;  losses  in  ship- 
ments of,  283  ;  Florida  law  on, 
283  ;    acid  test  for,  284. 

Improvement  through  bud  selec- 
tion, 115. 

Independent  shippers,  345. 

Infection,  by  spores,  277. 

Injuries,  to  fruit  in  packing,  322. 

Insect  pests,  bibliography,  496. 


Insects  and  control,  403. 

Inspection,  horticultural,  6. 

Insurance,  division  of  Exchange, 
350. 

Intercropping,  159. 

Interstate  Commerce  Commission, 
re-icing  rate  of,  298. 

Investment,  in  citrus  properties, 
359. 

Irrigating  system,  cost  of,  359. 

Irrigation,  179  ;  as  frost  protection, 
247  ;  overhead,  199  ;  by  basins, 
200  ;  by  furrows,  201  ;  depth  of, 
195 ;  frequency  of,  195 ;  cli- 
matic conditions  affecting,  188 ; 
of  newly  planted  trees,  158 ;  of 
nursery  stock,  91  ;  of  seed-bed, 
87  ;    bibliography,  482. 

Itinerant  packers,  344. 

Jacobs,  Louis,  21. 

Japan,  frost  in,  25. 

Japanese       privet,       affected       by 

mottled -leaf,  376. 
Jelly,  orange  and  lemon,  341. 
Jobber,  353. 
Jones,  B.  R.,  449. 
Judging  orchards    and    land,   363 ; 

references  to  literature,  486. 
Juice,  importance  in  judging,  134. 

Katydids,  430. 

Keeping  qualities,  effect  of  careful 
picking,  handling  and  packing 
on,  297. 

Kellerman  and  Wright,  cited,  379. 

Kerosene  emulsion,  formula  for 
black  scale,  410. 

Knots  on  limbs,  401. 

Koebele,  Albert,  6. 

Kumquat,  43,  44 ;  bibliography, 
472 ;  description  of,  varieties, 
Marunii,  Nagami,  83 ;  suscepti- 
bility to  frost,  242;  glaced,  341. 

Labeling,  of  boxes,  293  ;  "Sunkist" 
label,  292. 


512 


Index 


Labor,  cost  of,  360. 

Ladders,  picking,  280. 

Ladybird  beetle,  417  ;    for  cottony 

scale,  7. 
Land,  judging,  363;    cost  of,  359; 

stony  land,  development  of,  145  ; 

clearing  and  leveling,  145. 
Lath  house,   for  seed-bed,   86 ;     as 

protection  from  frost,  244. 
Lavanja  de  Umbigo,  13. 
Layering,  propagation  by,  92. 
Leaf-gumming,  368. 
Leaves,  season  of  fall,  49 ;    age  of, 

49 ;    variation  in  size  and  shape, 

49 ;    oil  glands  in,  50. 
Lefferts,  D.  C,  272. 
Legal  division  of  Exchange,  350. 
Lelong,  cited,  13,  11  ;  quoted,  33. 
Lemon,    black   pit   of,    401  ;     jelly, 

341  ;  peel  imported,  332  ;   grades, 

309;       storage,      306;       buttons 

dropping,    306  ;     sweating,    305  ; 

picking  rings,   305  ;    pools,   303  ; 

susceptibility  to  frost,  242  ;    as  a 

root-stock,  154  ;    length  of  period 

of  development,  54  ;   introduction 

into  Italy,  41  ;  bibliography,  469. 
Lemon   oil,    imported,    332 ;     tariff 

on,  9. 
Lemon  peel,  tariff  on,  9. 
Lemons,  core  rot  of,  382 ;    cost  of 

producing,    355 ;     picking,    302  ; 

separating     frosted     fruit,     273 ; 

varieties,  descriptions  of  Eureka, 

73  ;   Lisbon,  74  ;   Villafranca,  74  ; 

Bonnie    Brae,    75 ;     Genoa,    75 ; 

Sicily,  75;    Messina,  75 ;    Milan, 

75 ;    tarifT  on,  9  ;    standards,  for 

judging,  135 ;    sweet,  description 

of,  83. 
Lepidosaphes  beckii,  414. 
Level,  for  laying  off  contours,  151. 
Leveling  land,  145. 
Lime     (agricultural),     144;     as    a 

cure  for  mottled-leaf,  377. 
Lime     (tree),     bibliography,     471  ; 


susceptit)ility  to  frost,  242  ;  tariff 
on,  9 ;  description  of,  suscepti- 
bility to  frost,  varieties,  sour, 
West  Indian,  Rangpur,  Sweet, 
Mexican,  81 ;  juice,  preparation 
of,  339  ;  imported,  332  ;  oil,  im- 
ported, 332. 

Lime-magnesia  ratio,  377. 

Lipman,  C.  B.,  cited,  379. 

Lisbon  lemon,  pollination  of,  55. 

Litigation,  handled  by  Exchange, 
348. 

Local  Exchange,  346. 

Location,  for  grove,  357. 

Longevity  of  citrus  trees,  64. 

Los  Angeles,  headquarters  of  Ex- 
change, 346. 

Loughridge,  R.  H.,  quoted,  196. 

Lug-boxes,  as  carriers  of  infection, 
385 ;    fumigating  for  scale,  409. 

McAdie,  A.  G.,  cited,  237. 
Magnesia,    effect    on    mottled-leaf, 

377. 
Maintenance  and   repairs,   average 

cost  of,  361. 
Mal-di-gomma,  372. 
Malformation,  of  fruit,  326. 
Malforms  and  monstrosities,  120. 
Malnutrition,  371. 
Malva,  as  cover-crop,  183. 
Mandarin    oranges,     bibliography, 

471. 
Mandarins,    varieties,     description 

of  tangerine,   78  ;     Satsuma,  79  ; 

Unshiu,  79;    Dancy,  78;    King, 

78;    Beauty,   78;     Mikado,   78; 

Oneco,  78. 
Manifest  cord,  296. 
Maple,    affected    by    mottled-leaf, 

376. 
Marketing,  344  ;  bibliography,  490  ; 

disaster  of  1892-93,  7. 
Marmalades,  342. 
Marsh,  C.  M.,  76. 
Marsh  pomelo,  pollination  of,  55. 


Index 


513 


Mealy  bug,  discussion  of,  421. 
Mediterranean  fruit  fly,  quarantine 

against,  109. 
Melanose,  394. 
Meliola  camellise,  290,  407. 
Melon  aphis,  427. 
Membership,    in    Exchange,    349 ; 

in  Association,  357. 
Mesembryanthemum,  150. 
Mexico,  citrus  industry  of,  24. 
Miller,  Frank  A.,  22. 
Miner's  inch,  191. 
Mission  orchards,  distribution  from, 

2. 
Moisture  content,  of  soils,  196. 
Money,    remitted    by    salesmen    of 

Exchange,  350. 
Mononchus  papillatus,  454. 
Monstrosities,  120. 
Morelos  orange  worm,  24. 
Morse,  F.  W.,  431. 
Mother  trees,  for  bud-wood,  94. 
Mottled-leaf,    description    of,    374 ; 

causing  blemishes  on  fruit,  325 ; 

relation  to  nematodes,  449. 
Mulching,  173. 
Mules,  as  work  stock,  174. 
Mussey,  D.  N.,  303. 
Mutations,  120,  211. 
Mutual  protection,  division  of  Ex- 
change, 350. 

Nail-head  rust,  395. 
Nailing,  proper  method,  138. 
National  Orange  Show,  132. 
Navel,  importance  in  judging,  134. 
Needham,  J.  H.,  quoted,  74. 
Nematodes,    discovered    on    citrus, 

378 ;    on  citrus  roots,   449  ;    life 

history  described,  454. 
Neroli,  imported,  332  ;   tariff  on,  9  ; 

manufacture  of,  338. 
Newland,  Victor,  355. 
Nitrification  in  soil,  379. 
Nitrogen,    as  a  crop   limiter,    177  ; 

from  atmosphere,  165. 

2l 


North,  Judge,  founded  Riverside, 
17. 

Northern  California,  early  ripening 
in,  288. 

Northers,  as  affecting  frosts,  238. 

Norton,  J.  H.,  quoted,  124. 

Novius  cardinalis,  7. 

Nursery  stock,  84 ;  packing  for 
shipment,  102 ;  cultivation,  irri- 
gation, 102  ;  fertilization,  102 ; 
balling,  103 ;    naked  roots,  102. 

Nutrition,  derangement  of,  374. 

Oak  trees,  hosts  for  Armillaria 
mellea,  373. 

Off-bloom,  325. 

Oil,  as  a  fuel  for  orchard  heating, 
252 ;  of  anise,  used  in  gopher 
poison,  457 ;  of  bergamot,  im- 
ported, 332  ;  of  lemon,  imported, 
332  ;  of  lime,  imported,  332  ;  of 
neroli,  imported,  332. 

Old  age  decay,  of  stored  lemons, 
382. 

Oleander  scale,  420. 

Ontario  Fruit  Grower,  cited,  20. 

Orange,  tortrix,  428. 

Orange,  jelly,  341;  paste,  340; 
marmalade,  342 ;  wine,  337 ; 
juice,  unfermented,  335 ;  vine- 
gar, 336;  peel  imported,  332; 
susceptibility  to  frost,  242  ;  cause 
of  navel  in,  61  ;  pollination  ex- 
periments with,  56 ;  derivation 
of  word,  41 ;  time  required  in 
transit,  298  ;  shipping  under  ice, 
298 ;  number  of  fruits  per  box, 
195  ;  boxes  per  car,  295  ;  arrange- 
ment of  boxes  in  car,  295  ;  sweat- 
ing of,  282 ;  thinning  of  fruit, 
282  ;  picking  to  size,  282  ;  decays, 
277  ;  respiration  of,  277  ;  wrap- 
pers, cost  of,  355 ;  varieties, 
bibliography,  464  ;  oil,  imported, 
332  ;    tariff  on  oil,  9. 

Orange  diseases,  bibliography,  468. 


514 


Index 


Orange  growing  abroad,  bibliog- 
raphy, 463. 

Orange  growing  in  United  States, 
bibliography,  461. 

Orange  insects,  bibliography,  467. 

Orange  peel,  tariff  on,  9. 

Orange  standards,  for  judging, 
133. 

Oranges  and  lemons  of  India,  60. 

Oranges,  cost  of  producing,  355. 

Oranges  crystallized,  340. 

Oranges,  grades  of,  292  ;  tariff  on, 
9. 

Oranges,  varieties  of,  Valencia,  70  ; 
Excelsior,  70;  Hart's  Late,  71; 
Hart's  Tardiff,  71 ;  Valencia  Late, 
70;  Mediterranean  Sweet,  71; 
Paper  Rind,  St.  Michael,  72; 
Ruby,  72;  Ruby  Blood,  72; 
Jaffa,  72;  Joppa,  72;  Crafton, 
72  ;  Asher's  Best,  66  ;  Bostram's 
Prize,  66;  Washington  Navel, 
66  ;  Bahia,  66  ;  Riverside  Navel, 
66  ;  Thomson,  68  ;  Buckeye,  69  ; 
Navelencia,  69 ;  Nugget,  69 ; 
Australian,  69. 

Orchard  heaters,  requirements  of, 
253  ;  leakage  of,  255  ;  types  of, 
257  ;  installation  of,  259  ;  care  of, 
267. 

Orchard  heating,  230  ;  cost  of,  268  ; 
as  insurance,  33. 

Orchard  heating  operations,  264. 

Orchard  plans,  147 ;    tractors,  174. 

Orchards,  judging,  362. 

Organization,  references  to  litera- 
ture, 490. 

Origin  of  citrus  fruits,  25. 

Over-capitalization,  356. 

Overhead  irrigation,  as  a  protection 
from  frost,  199,  247. 

Overholtzer,  David,  199. 

Packed  box  standards,  for  judging. 

137. 
Packers,  293. 


Packing,  references  to  literature, 
489  ;  process  of.  295 ;  speed  in, 
295;  number  of  fruits  in  a  box, 
295  ;  ratio  of  field  to  packed  box, 
295 ;  average  cost  of,  360 ; 
lemons.  309. 

Packing-houses,  for  lemons,  314; 
arrangement,  299  ;  fire  hazard  in, 
301  ;  losses  from  fire,  301  ;  insur- 
ance for,  201  ;  number  of,  in  Cal- 
ifornia, 301 ;  capacity  of,  301  ; 
designing  and  construction  of, 
299. 

Palestine,  source  of  Jaffa  orange, 
72  ;    frost  in.  25. 

Parsons'  Navel  orange.  15. 

Parsons,  S.  B..  70,  15. 

Parthenocarpic  fruits,  55. 

Pedigreed  stock,  130. 

Penicillium  italicum  and  P.  digi- 
tatum,  causing  fruit  decays.  387. 

Performance  of  individual  trees, 
125. 

Performance  records.  128. 

Permanganate  of  potash,  use  as  dis- 
infectant. 291. 

Pests,  other  than  insects,  449  ;  dis- 
tribution of,  404  ;  financial  loss 
caused  by,  403  ;  inspection  and 
rjuarantine,  107  ;   145. 

Peteca.  causing  blemishes.  329. 

Petit  grain  oil.  preparation  of.  338. 

Phoma,  393. 

Phomopsis  citri.  394. 

Phosphoric  acid,  as  a  crop  limiter, 
177. 

Phyllosticta,  393. 

Physiological  derangements,  374. 

Pickers,  competition  between,  317; 
payment  of,  282. 

Picking,  done  by  associations,  347  ; 
average  cost  of,  360 ;  lemons, 
316;  ladders  for,  280;  oranges  to 
size,  282  ;  oranges,  care  in,  277 ; 
bags  for,  280. 

Picking  bags,  280. 


Index 


515 


Picking  lemons,  303. 

Picking  season,  orange,  277. 

Pipe  lines,  for  fuel  oils,  263 ;  for 
water,  193. 

Placing  of  fruit  in  boxes,  138. 

Plant-food,  amount  in  citrus  culls, 
177  ;    effect  of  bacteria  on,  165. 

Planting,  cost  of,  359,  160 ;  balled 
stock  versus  bare  root,  157 ; 
depth  of,  156 ;  time  of,  151  ; 
selection  of  site,  139 ;  seed-bed 
stock,  91;  147. 

Planting-board,  us  >  of,  156. 

Planting  plans,  147. 

Planting  seed,  87. 

Plant  lice,  427. 

Plowing,  165  ;  depth  of,  166  ;  time 
of,  166. 

Plows,  kinds  of,  166,  170. 

Plow-sole,  166  ;  as  affecting  irriga- 
tion, 203. 

Pocket  gopher,  456. 

Poison,  for  gophers,  457 ;  for 
ground  squirrels,  459. 

Poiteau,  40. 

Pollination,  123  ;  in  citrus  fruits  of 
Florida,  55;  in  citrus  fruits  of 
Southwest,  45. 

Polyembryony,  in  hybrids,  in 
citrus  seeds,  causes  of,  sig- 
nificance of,  59. 

Pomelo,  subject  to  canker,  392 ; 
susceptibility  to  frost,  242 ;  as  a 
rootstock,  152  ;  improvement  by 
hybridization,  118;  bibliography, 
472  ;  picking,  312  ;  tariff  on,  9  ; 
standards  for  judging,  136. 

Pomelos,  varieties,  description  of 
Marsh,  75  ;  Nectar,  77  ;  Duarte 
Seedling,  77 ;  Duncan,  77 ; 
Triumph,  77 ;  Imperial,  77 ; 
Colton,  77  ;    Pixik-fleshed,  77. 

Potash,  as  a  crop  limiter,  177. 

Potassium  cyanide,  for  fumigation, 
449. 

Powell,  G.  H.,  quoted,  353,  346. 


Precooling,  value  to  citrus  fruits, 
298 ;  definition  of,  297 ;  com- 
parison with  icing,  297  ;  amounts 
of  ice  required,  298. 

Precooling  plants,  297. 

Prickly  ash,  42. 

Privet,  Japanese,  affected  by 
mottled-leaf,  376. 

Production,  114,  25;  in  California, 
9. 

Profit  and  loss,  355. 

Propagation,  92 ;  references  to 
literature,  478. 

Propping  trees,  cost  of,  361. 

Protective  duties,  tariff,  9. 

Protective  League,  353. 

Pruning,  as  a  prevention  of  brown- 
rot,  387  ;  orange  trees,  207  ;  cost 
of,  359 ;  done  by  associations, 
347  ;  frosted  trees,  217  ;  time  of, 
216;  maxims  of,  215;  lemons, 
213  ;  training  nursery  trees,  205  ; 
general  considerations,  objects 
of,  204  ;    bibliography,  487. 

Prunings,  disposition  of,  217. 

Pruning  tools,  225. 

Pruning  wounds,  226. 

Pseudococcus  citri,  421. 

Puddling  roots,  155. 

Puffing,  329. 

Punctures,  caused  by  stems,  278 ; 
box-nails,  279  ;    thorns,  279. 

Purple  scale,  414. 

Pythiacystis  citrophthora,  365 ; 
causing  fruit  decay,  386. 

Quality,    in    tropical    grown    citrus 

fruits,  25. 
Quarantine,  horticultural,  6. 
Quincunx  planting,  148. 

Radiation,  234  ;    checking  of,  244  ; 

of  electric  orchard  heaters,  251. 
Rag,  importance  in  judging,  134. 
Railroads,  early  shipments  by  rail, 

5. 


516 


Index 


Rainfall,  26  ;  as  affecting  irrigation, 
188. 

Recipes,  341. 

Red  blotch  of  lemon,  described,  398. 

Red  rot,  see  red  blotch. 

Red  scale,  discussion  of,  411  ;  dis- 
tribution of,  404. 

Red  spiders,  discussion  of,  423. 

Reed,  J.  H.,  23. 

Refrigeration,  cost  of,  360. 

Reheading,  mature  trees,  220 ; 
young  trees,  218. 

Re-icing,  cost  of,  rate  case  con- 
cerning, 298. 

Relative  humidity  of  air,  as  affect- 
ing irrigation,  188. 

Relative  size  in  fumigation  dosage, 
451. 

Respiration,  of  oranges,  277. 

Reversion,  120. 

Rhizoctonia,  391. 

Right  of  diversion,  298. 

Rind,  importance  in  judging,  133  ; 
variation  in  thickness  of,  328. 

Ringing,  48. 

Rings  of  growth,  47. 

Ripening  season.  Northern  Valley, 
31. 

Risso,  40. 

Rivers,  Thomas,  70,  15. 

River's  Navel  orange,  16. 

Riverside,  first  settled,  3 ;  citrus 
fairs,  19,  5. 

Riverside  Press  and  Horticulturist, 
quoted,  19. 

Roosevelt,  President,  22. 

Root-rot,  due  to  sclerotinia,  383 ; 
due  to  toadstools,  373. 

Roots,  distribution  in  soil,  effect 
of  shearing,  45  ;  effect  of  hardpan 
on,  143 ;  injured  by  exposure  to 
air,  91  ;  cut  by  plow,  156 ;  of 
lemon,  susceptible  to  foot-rot, 
372  ;   affected  by  nematodes,  454. 

Root-stock,  151 ;  trifoliata  suitable 
for  kumquats,  83  ;   trifoliata  best 


for  Unshiu,  79 ;  cold  resisting, 
155  ;  proportion  of  different  kinds 
planted,  84;    Chinese  lemon,  6. 

Root  systems,  references  to  litera- 
ture, 481. 

Rose  beetle,  429. 

RutaceiE,  42. 

Saissetia  hemisphEerica,  420. 

Saissetia  olese,  405. 

Sales,  classification  of,  344 ;  divi- 
sion of  E.xchange,  350. 

Salesmen,  of  Exchange,  348. 

Salt  River  Valley,  23. 

San  Gabriel  Mission,  site  of  first 
orchard,  2. 

Santa  Fe  Railway,  5. 

Sap  Currents,  nature  of,  47  ;  rela- 
tion to  tree  parts,  47. 

Satsuma  orange,  production  of 
seeds  in,  56 ;  susceptibility  to 
frost,  242. 

Saunders,  William,  17. 

Savastano,  121. 

Saws,  for  pruning,  225. 

Scab,  description  of,  395. 

Scale  insects,  effect  of  climate  on, 
404  ;  exclusion  of,  357  ;  ridding 
seed-bed  stock  of,  90;  red,  411  ; 
yellow,  414;  black,  405  ;  purple, 
414;  brown,  418;  gray,  410; 
cottony  cushion,  417 ;  greedj', 
420  ;  citricola,  419  ;  hemispheri- 
cal, 420  ;    oleander,  420. 

Scales,  for  judging,  132. 

Scaly-bark,  367  ;  Florida  t>ije,  395. 

Scars,  on  fruit,  321. 

Schedules,  fumigation  dosage,  444- 
447. 

Schizophyllum  commune,  399. 

Scientific  American,  48. 

Scions,  references  to  literature,  478. 

Sclerotinia  libertiniana,  causing 
fruit  decay,  382. 

Score-card,  for  citrus  land,  139; 
for    bearing    groves,    363  ;     for 


Index 


517 


oranges,    133 ;    for  lemons,    134 ; 

for    pomelos,    136 ;     for    packed 

boxes,  137  ;    for  feature  exhibits, 

138. 
Scratches,     caused     by     shoes     of 

pickers,  280 ;    caused  by  finger- 

naUs,  279  ;    gravel,  279  ;    thorns, 

279. 
Scutellista  cyanea,  409. 
Season,  of  picking,  63. 
Seed-bed,  planting,  84. 
Seed-bed    stock,    price,    method    of 

pulling,  88  ;   trimming  back  when 

transplanting,  92. 
Seed,  citrus,  description  of  different 

kinds,  84;    cost,  84;    method  of 

keeping,  86  ;   number  per  bushel, 

86. 
Seedlessness,     importance     of     in 

pomelos,  77. 
Seedling     trees,     compared     with 

budded  trees,  65  ;  84. 
Seeds,  presence  of,  in  judging,  134, 

136  ;   time  of  planting,  88  ;   effect 

of  freezing  on   germination,   86 ; 

first  planted  in  (California,  1. 
Seeds  of  citrus  fruits,   number  of, 

61. 
Selected  buds,  importance  of,  357. 
Selection    of    bud-wood,    effect    of 

poor  bud-wood,  1 14. 
Selling,  average  cost  of,  360. 
Separators,  for  frosted  fruit,  272. 
Setting  of  fruit,  as  affected  by  plow- 
ing, 166. 
Seville    orange,     susceptibility     to 

frost,  242. 
Shaddock,  description  of,  81. 
Shading,  of  nursery  plants,  38. 
Shamel,  A.  D.,  124. 
Shears,  for  pruning,  225. 
Shields,  for  tillage  implements,  170. 
Shipments,  annual,  in  carloads,  9. 
Shipping,    lemons,    312 ;     first    car 

shipped  east,  3 ;    nursery  stock, 

103. 


Shorb,  J.  de  Barth,  18. 

Shoulder  spots,  323. 

Silver  mite,  discussion  of,  424. 

Silverware,  as  premiums,  351. 

Site,  for  planting,  139. 

Six-spotted  mite,  423. 

Size,  importance  in  judging,  135. 

Sizing,  lemons,  310;  machines, 
292. 

Slitting  bark,  of  young  trees,  206. 

Slope,  of  land  for  irrigation,  201  ; 
best  for  planting,  150. 

Smith,  C.  O.,  cited,  401. 

Smith,  R.  E.,  quoted,  378. 

Smoke,  from  orchard  heaters,  253. 

Smudge  fuel,  250. 

Snowden,  R.  R.,  cited,  377. 

Sodium  cyanide,  for  fumigation, 
449. 

Sodium  sulfate,  a  waste  product  of 
fumigation,  439. 

Soft  brown  scale,  discussion  of,  418. 

Soil,  nitrification  and  ammonifica- 
tion,    379 ;     heavy   soil   may   en- 
courage gum-disease,  365 ;    most 
desirable,     357 ;      samples,     196 
inoculation,    183;    tillage  of,  165 
alkali,  144  ;   ideal  for  citrus,  144 
for  seed-bed,  87. 

Soil  acidity,  144. 

Soil  adaptations,  142. 

Soil  analysis,  144. 

Soils,  relation  to  mottled-leaf,  378  ; 
kinds  as  affecting  method  of  irri- 
gation, 200  ;  kinds  not  benefited 
by  cover-crop,  183  ;  humus  con- 
tent, 179  ;  analyses  of,  175  ;  cul- 
tivation and  management,  170 ; 
for  seed-bed  stock,  91  ;  northern 
coast  division,  32 ;  Interior 
Valley  division,  31 ;  Southern 
Coast  division,  29  ;  references  to 
literature,  481. 

Soil  scars,  on  fruit,  323. 

Soil  types,  142. 

Solauum  nigrum,  404. 


518 


Index 


Sonora,  citrus  production  in,  23. 

Sour  clover,  as  cover-crop,  182. 

Sour-stock,  as  a  root,  152. 

South  Africa,  14  ;    frost  in,  25. 

Southern  Pacific  Railway,  5. 

Spain,  frost  in,  25. 

Special  equipment,  for  packing- 
houses, 299. 

Speculation,  encouraged  by  over- 
capitalization, 356. 

Speculators,  344. 

Sphceropsis  tumefaciens,  401. 

Sphagnum,  for  packing  bud-wood, 
94 ;  for  packing  seed-bed  stock, 
90. 

Splits,  as  blemishes,  326. 

Splitting  of  bark,  effect  of  frost  on, 
219. 

Spores,  of  fungi  in  wash  water,  385. 

Spotting,  of  Navel  oranges  in  tran- 
sit, 389. 

Spraying,  cost  of,  361. 

Spraying  under  trees,  as  prevention 
for  brown-rot,  387. 

Square  planting,  148. 

Squirrels,  as  pests,  458. 

Staking  young  trees,  in  orchard, 
218. 

Standard  car,  number  of  boxes  in, 
295;  arrangement  of  boxes  in, 
295  ;    air  spaces  in,  296. 

Standard  grade,  292. 

Standpipes,  for  irrigation,  194. 

State  Commission  of  Horticulture, 
influence  on  industry,  11 ;  descrip- 
tion of,  106. 

State  Fruit  Growers'  Convention, 
109. 

Statute  inch,  192. 

Stem,  importance  in  judging,  133. 

Stem  end  rot,  394. 

Stem  end  spot,  in  California,  399 ; 
of  oranges,  320. 

Stem  punctures,  321,  278. 

Stenciling,  of  boxes,  293 ;  impor- 
tance in  judging,  137. 


Stevens,  H.  E.,  cited,  392. 

Stock,  see  Root-stock,  152. 

Stocks,  references  to  literature,  478. 

Storage,  306. 

Storing,  references  to  literature, 
489. 

Strap,  proper  position  of,  138. 

Straw,  plowed  under,  a  cause  of 
mottled-leaf,  379. 

Structure  of  the  fruit,  morphologi- 
cal, 60. 

Strychnine,  as  poison  for  gophers, 
457. 

Subsoiling,  166. 

Subsoils,  143. 

Sucker  growths,  208. 

Sucker-nests,  226. 

Suckers,  effect  of  presence  of,  209 ; 
not  desirable  for  bud-wood,  95. 

Sucking  insects,  405. 

Sugar,  reduction  of,  during  respira- 
tion, 287. 

Sugars,  in  citrus  fruit,  63. 

Sulfur,  remedy  for  red  spider,  424. 

Sulfuric  acid,  for  fumigation,  439. 

Sunburn,  of  bark,  encourages  schizo- 
phyllum,  400. 

Sunburn,  of  leaves,  368 ;  of  fruit, 
324. 

Sunburning,  bark  of  pruned  trees, 
219. 

"Sunkist"  label,  292,  351. 

Sunlight,  effect  of  over-illumina- 
tion, 38  ;  as  affecting  irrigation, 
188. 

Sun  protectors,  157. 

Supply  cart,  for  fumigators,  438. 

Supply  Department,  of  Exchange, 
350. 

Sweating,  lemons,  305 ;  oranges, 
282;  of  Valencia  oranges,  282; 
references  to  literature,  489. 

Sweat  room,  description  of,  289, 
305  ;  construction  of,  289  ;  tem- 
perature of,  290  ;  heating  of,  290  ; 
arrangement  of  fruit  in,  290, 


Index 


519 


Sweet  orange,  antiquity,  introduc- 
tion into  Europe,  introduction 
into  Brazil,  41. 

Swingle,  W.  T.,  79. 

Swingle-Webber  hybrids,  varieties, 
Rusk,  79;  Willits,  79;  Norton, 
79;  Colman,  79;  Savage,  79; 
Rustic,  79  ;  Thornton,  80 ;  Samp- 
son, 80  ;  Weshart,  80  ;  Trimble, 
80. 

Taber,  G.  L.,  cited,  155. 

Tait,  C.  E.,  quoted,  170. 

Tangelo,  79. 

Tangerines,  picking,  312. 

Tanking  newly  planted  trees,   158. 

Tannin,  treatment  for  fumigating 
tents,  435. 

Tar,  for  pruning  wounds,  228. 

Tariff,  references  to  literature,  490  ; 
protective  duties,  9. 

Taxes,  357 ;  and  incidentals,  cost 
of,  359. 

Teague,  R.  M.,  77,  69. 

Temperature,  effect  on  fumigation, 
448 ;  of  air,  as  affecting  irriga- 
tion, 188. 

Tent  fumigation,  of  citrus  trees, 
435. 

Tents,  for  storing  lemons,  308 ; 
cost  of,  452 ;  acid  holes  in,  438  ; 
equipment  of,  437 ;  methods  of 
marking,  436  ;    fumigation,  435. 

Teratological  forms,  326,  120. 

Terraced  planting,  150. 

Tetranychus  mytilaspidis,  423. 

Tetranychus  sexmaculatus,  423. 

Texture,  importance  in  judging, 
136. 

Thawing,  of  frozen  fruit,  249. 

Thermal  l^elts,  236. 

Thinning,  of  fruit,  323 ;  advis- 
ability of,  282. 

Thomas,  E.  E.,  cited,  378,  449. 

Thomson,  A.  C,  68. 

Thorns,  51. 


Thorn-stabs,  321. 

Thrips,  discussion  of,  425. 

Tibbet,  Luther  C,  and  wife,  17,  18. 

Tillage,  165. 

Tincture  of  orange  flowers,  338. 

Toadstool  root-rot,  373. 

Tomocera  californica,  410. 

Tools,  for  pruning,  225. 

Topography,  as  affecting  frosts,  238. 

Top-working,  223,  92. 

Tortrix  citrana,  description  of,  428. 

Tractors,  for  plowing,  168. 

Traffic,  division  of  Exchange,  350. 

Training  young  trees,  100. 

Transit,  time  required  for,  dis- 
tance covered,  298. 

Transpiration,  in  fruit,  61. 

Trapping  gophers,  456. 

Tree  protectors,  157. 

Tree-ripes,  305 ;  lemons,  suscep- 
tible to  black  pit,  401. 

Trees,  cost  of,  359 ;  number  of,  to 
the  acre,  149. 

Triangular  planting,  147. 

Trifoliata,  susceptibility  to  frost, 
242  ;    as  a  root-stock,  153. 

Trifoliate  orange,  rare  in  California, 
83. 

Tripeta  ludens,  24 ;  quarantine 
against,  109. 

Trunk  rot,  399. 

Turgidity  of  rind,  dangers  from, 
278. 

Twelve-spotted  beetle,  430. 

Twig  blight,  382. 

Twig-gumming,  367. 

Tylenchulus  semipenetrans,  449. 

Types,  of  fruit,  123. 

Underwood-Simmons  tariff,  9. 

University  of  California,  11. 

U.   S.   Department  of  Agriculture, 

citrus  hybrids  distributed  by,  79  ; 

influence  on  industry,  11. 
U.  S.  Supreme  Court,  decision  in 

pre-cooling  case,  298. 


520 


Index 


Vaile,  R.  S.,  455. 

Valencia  orange,  how  pruned,  212; 
sweating  of,  282  ;  origin  of  and 
conditions  best  suited  for,  70 ; 
pollination  of,  55. 

Varieties,  descriptions  of,  65 ;  bib- 
liography, 485. 

Vegetables,  grown  between  trees, 
159. 

Ventilation,  for  stored  lemons,  308. 

Verrucosis,  395. 

Vesicles,  as  affected  by  frost,  274  ; 
arrangement  of,  60. 

Vetch,  as  host  for  cottony  mold, 
383 ;  common,  as  cover-crop, 
182  ;    hairy,  as  cover-crop,   182. 

Vicia  sativa,  as  cover-crop,  182. 

Vinegar,  from  oranges,  336. 

Wages,  of  lemon  pickers,  317. 

Wagons,  304. 

Wallace,  J.  C,  16. 

Washington  Navel  orange,  descrip- 
tion of,  climatic  and  soil  condi- 
tions best  suited  to,  sporting 
habits,  sub-varieties,  66 ;  com- 
position of,  62  ;  seedlings  of,  59  ; 
production  of  seeds  in,  occur- 
rence of  normal  embryo  sacs  in, 
56-57  ;  pollination  of,  55  ;  his- 
tory of  introduction,  first  ex- 
hibited in  California,  19  ;  present 
location  of  two  trees  first  brought 
to  California,  23  ;  sports  of,  128 ; 
how  pruned,  207. 

Wash  water,  disinfection  of,  291. 

Water,  amount  necessary  for  irri- 
gation, 188  ;  application  to  young 
trees,  158 ;  disposition  of  waste, 
150,  144  ;  loss  of,  from  fruit,  61  ; 
average  cost  of,  361  ;  methods 
of  application,  198 ;  time  of 
application,  195 ;  temperature 
of,  196  ;  methods  of  distribution, 
193;  lifting,  for  irrigation,  193; 
underground,  laws  in  regard  to, 


192 ;  cost  of,  193 ;  sources  of, 
192;  measurement,  191. 

Watering  seed-beds,  391. 

Water  right,  142  ;    cost  of,  359. 

Water  supply,  importance  of,  357 ; 
for  irrigation,  141. 

Webber,  H.  J.,  79. 

Weeds,  as  hosts  for  scale  insects,  404. 

White,  A.  S.,  19. 

White  fly,  quarantine  against,  109. 

Whitewash,  for  pruning  wounds, 
228 ;  prevents  sunburn  of  bark, 
219. 

Wind,  as  affecting  frost,  233,  235 ; 
as  affecting  irrigation,  188;  arti- 
ficial, as  frost  protection,  248 ; 
causing  blemishes  of  fruit,  320; 
effect  on  fumigation,  448. 

Windbreaks,  37,  38. 

Windfalls,  324. 

Winds,  effect  on  trees,  36. 

Wire  baskets,  250. 

Wither-tip,  description  of,  380. 

Woglum,  R.  S.,  433. 

Wolf  &  Massey,  393. 

Wolfskin,  Louis,  17. 

Wolfskin,  William,  first  commer- 
cial orchard,  2. 

Wood,  structure,  46. 

Woodworth,  C.  W.,  446;  dosage 
table,  450. 

Workman,  C.  R.,  74. 

Works,  J.  D.,  cited,  161. 

Wounds,  dressings  for,  226 ;  heal- 
ing of,  49. 

Wrappers,  redeemable  for  pre- 
miums, 351. 

Wrapping,  value  in  judging,  138. 

Xanthoxylum  americanum,  42. 

Yellow  scale,  discussion  of,  414. 
Yellow  spotting  of  oranges,  398. 
Yields,   127,   129,  359;    lemon  and 

orange  compared,   191 ;    average 

obtained,  362. 
Yuma,  citrus  planting  at,  23. 


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CITRUS  FRUITS  AN  ACCOUNT  OF  THE  CITRUS  FRUIT 

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